This is a list of characters in the universe of Cartoon Network's Ben 10 franchise.^[1][2]

• This table shows the recurring characters and the actors who have portrayed them throughout the franchise.
• A dark grey cell indicates the character was not in the series or film, or that the character's presence in the series or film has not yet been announced.
• A ^Y indicates an appearance as a younger version of a pre-existing character.
• A ^C indicates a cameo appearance.
• A ^P indicates an appearance in onscreen photographs only.
• A ^D indicates an appearance in deleted scenes only.
• A ^M indicates a motion-capture role.
• A ^U indicates an uncredited role.

  = Main cast

  = Recurring cast

  = Guest cast

Characters	Ben 10 (2005)	Ben 10: Alien Force	Ben 10: Ultimate Alien	Ben 10: Omniverse	Ben 10 (2016)
	2005–2008	2008–2010	2010–2012	2012–2014	2016–2021
	Team Tennyson
Benjamin Kirby "Ben" Tennyson Ben 10	Tara Strong	Yuri Lowenthal	Yuri Lowenthal		Tara Strong
			Tara StrongYC	Tara StrongY	Yuri LowenthalC
Gwendolyn "Gwen" Tennyson Lucky Girl	Meagan Smith	Ashley Johnson		Ashley Johnson	Montserrat Hernandez
Magister Maxwell "Max" Tennyson Grandpa Max	Paul Eiding	Paul Eiding			David Kaye
Kevin Ethan Levin Kevin 11	Michael Reisz	Greg Cipes		Greg Cipes
	Charlie Schlatter
Rook Blonko				Bumper Robinson

• This table shows the recurring characters and the actors who have portrayed them throughout the franchise.
• A dark grey cell indicates the character was not in the series or film, or that the character's presence in the series or film has not yet been announced.
• A ^Y indicates an appearance as a younger version of a pre-existing character.
• A ^C indicates a cameo appearance.
• A ^P indicates an appearance in onscreen photographs only.
• A ^D indicates an appearance in deleted scenes only.
• A ^M indicates a motion-capture role.
• A ^U indicates an uncredited role.

Characters	Film series					Special
	Ben 10: Secret of the Omnitrix	Ben 10: Race Against Time	Ben 10: Alien Swarm	Ben 10: Destroy All Aliens	Ben 10 Versus the Universe: The Movie	Ben 10/Generator Rex: Heroes United
	2007		2009	2012	2020	2011
	Team Tennyson
Benjamin Kirby "Ben" Tennyson Ben 10	Tara Strong	Graham Phillips	Ryan Kelley	Tara Strong		Yuri Lowenthal
Gwendolyn "Gwen" Tennyson Lucky Girl	Meagan Smith	Haley Ramm	Galadriel Stineman	Meagan Smith	Montserrat Hernandez	Silent cameo
Magister Maxwell "Max" Tennyson Grandpa Max	Paul Eiding	Lee Majors	Barry Corbin	Paul Eiding	David Kaye
Kevin Ethan Levin Kevin 11			Nathan Keyes		Greg Cipes
Rex Salazar						Daryl Sabara

Voiced by:

• Tara Strong – Ben 10 (2005), Ben 10: Ultimate Alien, Ben 10: Omniverse & Ben 10 (2016) (child)
• Yuri Lowenthal – Ben 10: Alien Force, Ben 10: Ultimate Alien, Ben 10: Omniverse & Ben 10 (2016) (teenager)

Portrayed by:

• Graham Phillips – Ben 10: Race Against Time
• Ryan Kelley – Ben 10: Alien Swarm

Ben Tennyson is the titular character and the main protagonist of the franchise. At the start of Ben 10, he is a 10-year-old boy^{[note 1]} from Bellwood who, during his summer vacation, discovers the Omnitrix, a prototype device that attaches to his wrist and allows him to transform into various aliens. He uses the Omnitrix to become a superhero while traveling across the USA. After the Omnitrix is destroyed at the end of Alien Force, Ben retrieves the Ultimatrix from Albedo and uses it as a replacement. At the end of Ultimate Alien, Azmuth takes the Ultimatrix away and gives Ben the official Omnitrix.

Voiced by:

• Meagan Smith – Ben 10 (2005)
• Ashley Johnson – Ben 10: Alien Force, Ben 10: Ultimate Alien, & Ben 10: Omniverse
• Montserrat Hernandez – Ben 10 (2016)

Portrayed by:

• Haley Ramm – Ben 10: Race Against Time
• Galadriel Stineman – Ben 10: Alien Swarm

Gwen Tennyson is Ben's paternal cousin. In the original series, Gwen shared a love-hate family relationship with Ben. Before discovering and reinventing her dormant magic powers, she helped Ben using her innate intelligence; she is also a talented martial artist who has received black belts in karate and taekwondo. Gwen is a model student, and in Omniverse, she is shown leaving for an Ivy League College.

Gwen is able to manipulate mystical energy named "mana" to create energy blasts, shields, and other constructs. She later learns that her powers are not magic in origin, but rather alien, and her paternal grandmother, Verdona, is a powerful Anodite alien who can manipulate mana, the essence of magic and life.^[3] Gwen cannot take on a fully Anodite form at will unless she masters it.

Voiced by:

• Paul Eiding – Ben 10 (2005), Ben 10: Alien Force, Ben 10: Ultimate Alien & Ben 10: Omniverse (adult)
• Adam Wylie – Ben 10 (2005) (child)
• Jason Marsden – Ben 10: Ultimate Alien (teenager)
• David Kaye  – Ben 10 (2016)

Portrayed by:

• Lee Majors – Ben 10: Race Against Time
• Barry Corbin – Ben 10: Alien Swarm

Max Tennyson is Ben and Gwen's paternal grandfather. He is 60 years old in the original series, 65 in Alien Force and the reboot, 66 in Ultimate Alien and Omniverse, 80 in Ben 10,000 and 92 in Ken 10.^{[note 2]} Despite his age, he is shown to be an experienced capable fighter, and after Ben finds the Omnitrix, supports him any way he can. Max was once a candidate for the Apollo 11 mission and one of the leaders, or "Magisters", of the Plumber organization, but Ben and Gwen did not know of this at first, believing him to have been a literal plumber.

Kevin Ethan Levin (voiced by Michael Reisz in the original series episode "Kevin 11", Charlie Schlatter in later episodes of the original series, and Greg Cipes in subsequent series; portrayed by Nathan Keyes in Alien Swarm) is an half alien-human who can absorb matter, energy, and DNA and initially appears in the original series as an 11-year-old^{[note 3]} boy and one of Ben's enemies. Believing his stepfather Harvey Hackett convinced his mother to abandon him after he accidentally destroyed his family's house when his powers first manifested, Kevin ran away and ended up living in the subway of New York City, where he met Ben and used him to siphon the Omnitrix's energies to get back at those who demonized him. However, Kevin was also infused with the DNA of the aliens Ben had access to at the time and became a chimeric hybrid of the alien forms, which rendered him psychotic and unstable.^[4]

Later in the series, Kevin ends up in the Null Void, where he manages to regain his normal form and master his abilities under the guidance of a fellow inmate. He then escapes and is found by the Rooters, who train him and use his power to turn themselves and the Plumbers Kids into alien hybrids to further the organization's plan to assassinate Ben. This attempt later ends in failure with Kevin's memories altered to have no recollection of the Rooters, which makes him believe his father was an alien involved with the intergalactic black market. Despite lacking a formal education, Kevin possesses a vast knowledge of alien life and paraphernalia. While teaming up with Ben and Gwen during the Highbreed invasion of Earth, the false memories of his father influence Kevin to reconcile with Ben and, over time, he becomes romantically involved with Gwen.

In the reboot series, Kevin is a normal human who wields the Antitrix, a duplicate of the Omnitrix that Vilgax helped him build. The Antitrix aliens are corrupted versions of the Omnitrix aliens who are spliced with DNA of other unidentified species.He built the Antitrix in cave,with blueprints provided by vilgax in his dream.

Rook Blonko (voiced by Bumper Robinson) is a Revonnahgander Plumber who Max assigns to work with Ben after Gwen and Kevin leave Bellwood for college. Rook is a top Plumber Academy graduate and skilled fighter who wields the Proto-tool, a shapeshifting weapon that can transform into various tools.^[5]

The Plumbers are an intergalactic police force. While very few of them work on Earth, most work in different parts of the universe.

Among the known Plumbers are:

• Magister Labrid (voiced by Jeff Bennett) is an Aquarian Plumber who recruited Max into the group. In the Alien Force pilot episode "Ben 10 Returns", Labrid is killed in battle with the Forever Knights.
• Magister Prior Gilhil (voiced by J. K. Simmons) is Max Tennyson's superior and the guardian of several hundred planets. He is later killed by Aggregor.
• Magister Patelliday (voiced by Rob Paulsen) is a Pisciss Volann Plumber and the second-in-command of the Plumbers on Earth.
• Magister Hulka (voiced by Miguel Ferrer) is a drill instructor at the Plumbers' Academy.

This group is composed of the children of Plumbers, most of whom are superpowered alien-human hybrids. In Omniverse, it is revealed that they were artificially mutated by Servantis using Kevin's abilities and had their memories manipulated to make them believe that they were born hybrids.

Cooper (voiced by Cathy Cavadini in the original series, Corey Padnos in Alien Force, Chris Pratt in Ultimate Alien, Eric Bauza in Omniverse) is a mutant human who can manipulate machinery. In Ultimate Alien, Cooper has shown to have had a growth spurt and is now considerably taller and more muscular. He reappears in "Prisoner #775 is Missing", where he is revealed to have joined the Plumbers.

Alan Albright (voiced by Zeno Robinson in Alien Force and Ultimate Alien, Bumper Robinson in Omniverse) is a Pyronite hybrid who can return to his human form at will, unlike the other Plumbers' Helpers.

Helen Wheels (voiced by Juliet Landau) is a Kineceleran hybrid and friend of Manny. The two used to hunt aliens they confused for criminals whom they would throw into an old Null Void projector, which they mistook for a disintegration weapon. Manny convinces Helen that Ben, Gwen and Kevin are DNAliens, but the confusion is eventually cleared up after Ben proves that the Null Void projector was not a disintegration weapon.

Manny Armstrong (voiced by Khary Payton) is a Tetramand hybrid and friend of Helen. The two formerly hunted aliens before realizing their wrongs and reforming. Manny is like Kevin: hot-headed, aggressive, a rebel and sometimes cocky, often willing to fight even when it may be not necessary. He shows an anti-hero personality and is stubbornly dedicated to their mission, immediately assuming that Ben, Gwen, and Kevin are DNAliens. Manny is finally convinced to listen after being brought down by Ben.

Pierce Wheels (voiced by Adam Wylie) is a hybrid of Argit's species and Helen's adoptive brother. He has the ability to sprout quills from anywhere on his body, which he uses in tandem with his martial art skills. He first appears in a recorded journal having reportedly died in the "disintegration weapon" during a mission while working with Helen and Manny, but it is later revealed that he was actually sent to the Null Void. Pierce re-appears in the Ultimate Alien episode "The Purge", where he uses an ID mask to pose as a human and go on a date. He is confronted by two Forever Knights members, who beat him to death when he refuses to leave Earth.

Lucy Mann (voiced by Tara Strong) is a Lenopan, a slimy shapeshifting alien and Ben's cousin-in-law. In the original series, Lucy briefly appears in "My Big Fat Alien Wedding", as she is the flower girl in the wedding between her aunt Camille and Ben's uncle Joel as part of creating a truce between the warring groups. Lucy later appears in Omniverse, where she has joined the Plumbers.

Julie Yamamoto (voiced by Vyvan Pham) is an Asian-American girl and tennis champion who was a classmate of Ben and goes on to be romantically involved with him. Julie is the owner of Ship (also voiced by Vyvan Pham), a dog-like Galvanic Mechamorph who can transform into a suit of powered armor for her use.

Kai Green (voiced by Bettina Bush) is a Native American and one of Ben's love interests. She is the granddaughter of Wes Green, who was an old friend of Max Tennyson and a former Plumber. In a potential future depicted in Omniverse, Kai goes on to marry Ben, with whom she has a son named Kenny.

Azmuth (voiced by Robert David Hall in the original series, Jeff Bennett in Alien Force and Ultimate Alien, René Auberjonois in Omniverse, and David Kaye in the reboot) is a thousand-year-old Galvan scientist and the creator of the Omnitrix and the Galvanic Mechamorphs.

Thousands of years prior to the series, Azmuth was in a relationship with a fellow Galvan named Zennith. During this time, a rare planetary alignment inspired him to create Ascalon, a powerful weapon capable of manipulating fundamental forces.

After Ascalon was used by another being in an attempt to end a civil war on the Incursean homeworld, which resulted in the planet's destruction, Azmuth recognized the consequences of creating such a weapon. He subsequently chose to hide Ascalon and entrusted it to Sir George, who later used it to defeat Dagon.

Professor Paradox (voiced by David McCallum) is a time traveler who received government funding to work on breaking a hole in the space-time continuum during the Cold War. A miscalculation caused Paradox to get sucked into the Event Horizon, where he remained displaced from time for 100,000 years. Losing his mind and regaining his sanity, he gained a complete understanding of the space-time and renamed himself Paradox. Paradox uses the Chrononavigator to traverse space and time, which initially appears in the series as a pocket watch.^[6]

J. Jonah "Jimmy" Jones (voiced by Scott Menville) is a fan of Ben who exposed his secret identity to the world in Ultimate Alien. He is named in reference to the Marvel Comics character J. Jonah Jameson.^[7].He was shown 10 years-old in the series..^[7]

Aggregor's prisoners (also called the Andromeda Five) are a group of aliens from the Andromeda Galaxy who Aggregor captured to absorb their powers and claim the Map of Infinity. They consist of the Orishan Bivalvan, the Prypiatosian-B P'andor, the Talpaedan Andreas, and the Amperi Ra'ad (all voiced by Dee Bradley Baker), and the Geochelone Aerio Galapagus (voiced by John DiMaggio).

Sir George (voiced by Peter Renaday) is an immortal knight who founded the Forever Knights to combat Dagon. Sir George forged the seal that kept the Lucubra in the 4th century. In 1131, he defeated another extra-dimensional creature known as Dagon with the sword Ascalon, created and given to him by Azmuth. George carved out Dagon's heart and pinned it to the ground with his sword, becoming the basis for the legend of Saint George and the Dragon. In the present day, George reunites the factions of the Forever Knights to combat Dagon, but is killed when Dagon strips him of his immortality.

Glitch (voiced by Tara Strong) is a character originating from the reboot continuity and a human-Galvanic Mechamorph hybrid who was created after Ben used Upgrade to enhance the Omnitrix.He made as a clone of Ben with a mixture of Upgrade due to malfunctioning in DNA tubes inside the omnitrix .He is initially trapped in the Omnitrix before Ben frees him in the episode "Innervasion". Vilgax kills Glitch in Ben 10 Versus the Universe: The Movie, though Phil promises to recover his remains and resurrect him. In a potential future depicted in the episode "Ben 10,010", Glitch is converted into a drone-like form dubbed Hitch.

Ken Tennyson (voiced by Tara Strong in the original series, Scott Menville in Omniverse) is Ben's future son. Kenny first appears in the original series episode "Ken 10", where he receives a duplicate of the Omntrix created by his father. In Omniverse, Kenny is grounded and has his Omnitrix taken away. After gaining time travel technology from Paradox, Kenny takes the identity of Chrono Spanner and travels back in time to aid Ben's younger self.

Ben 23 (voiced by Tara Strong) is a rich and younger version of Ben from Dimension 23, being a celebrity in his universe with his own agent. In contrast to Ben, Ben 23's alien transformations are predominantly blue rather than green and have different names than the prime Ben. Making his debut in "Store 23" when Ben ended up in Dimension 23, Ben 23 is revealed to only got the Omnitrix after his universe's version of Max Tennyson died. As a result, Ben 23 taught himself how to use the Omnitrix while on the notion that all aliens are evil. The prime timeline Ben's interference allows Ben 23 to understand that not all aliens are evil.

Ben 10,000 (voiced by Fred Tatasciore in the original series and reboot, Sean Donnellan in Ultimate Alien, Judd Nelson in Omniverse) is the name of several alternate future versions of Ben.^[8]

The Ben 10,000 depicted in the original series comes from a future where humans and aliens live in co-existence and he has unlocked 10,000 different alien transformations. Ben becomes unable to take time off, not even for his own family, until he is convinced otherwise by a time-traveling younger Ben. As revealed in "Ken 10", Ben 10,000 is married to Kai Green and they have one child: Kenny, who was given a replica of the Omnitrix.

The Ben 10,000 depicted in Ultimate Alien retained the Ultimatrix and can access the abilities of his alien forms without transforming. He appears in "Ben 10,000 Returns", where Ben 10,000 seeks his past self's help in fighting off Eon.

The original Ben 10,000 returns in Omniverse, where he wields the Biomnitrix - dual Omnitrixes that allow him to transform into hybrid alien forms.

Gwen 10 (voiced by Meagan Smith in the original series, Ashley Johnson in Omniverse) is an alternate universe version of Gwen who found the Omnitrix instead of Ben.

Cash and JT are Ben's old bullies from school. Cash is voiced by Dee Bradley Baker in the original series, Matt Levin in Alien Force and Ultimate Alien, and Roger Craig Smith in the reboot, and portrayed by Tyler Patrick Jones in Race Against Time. JT is voiced by Adam Wylie in the original series, Scott Menville in Alien Force and Ultimate Alien, and Max Mittelman in the reboot, and portrayed by Tyler Foden in Race Against Time. The two are modeled after series producers Sam Register and Tramm Wigzell.

Lt. Steel (voiced by Michael Gough in the original series, Yuri Lowenthal in Omniverse) is the leader of SECT, a task force that deals with alien criminals. He initially regards Ben and all aliens as a menace due to the actions of Kevin, who was posing as Ben. However, after Ben saves his life, Steel returns the favor by clearing his name.

Tetrax Shard (voiced by Dave Fennoy in the original series and Alien Force, Todd Haberkorn in the reboot) is a Petrosapien and former mercenary. Tetrax was originally a selfish bounty hunter until he accepted a job to steal a sacred Petropian crystal and deliver it to Vilgax. Vilgax uses the crystal to destroy Petropia, causing Tetrax immense guilt until the planet is restored in the Alien Force episode "The Secret of Chromastone".

In the reboot, Tetrax is unaffiliated with Vilgax. He initially works with Kraab and SixSix before separating from them, with Kraab ripping off his left arm in a later fight.

Xylene (voiced by Grey DeLisle) is an Uxorite and friend of Max who sent the Omnitrix to Earth.

The Galactic Enforcers are a group of alien heroes. They consist of Ultimos (voiced by Tom Kane in the original series and Jeff Bennett in Alien Force), a humanoid alien akin to Superman; Synaptak (voiced by Greg Ellis), a psychic squid-like alien; and Tini (voiced by Vanessa Marshall in the original series and Juliet Landau in Alien Force), a Tetramand.

Myaxx (voiced by Vanessa Marshall in the original series, Vyvan Pham in Alien Force) is a Chimera Sui Generis and Azmuth's former assistant. She stopped working for Azmuth because he did not give her the credit she felt she deserved.

Carl Tennyson (voiced by Dee Bradley Baker in the original series, Don McManus in Alien Force and Race Against Time, Yuri Lowenthal in Ultimate Alien) and Sandra Tennyson (voiced by Tara Strong in the original series, Vyvan Pham and Beth Littleford in Alien Force, and Littleford alone in subsequent series) are Ben's parents. In Alien Force, Carl and Sandra punished Ben for using the Omnitrix until that they found out that Ben is trying to protect the world. In Ultimate Alien, Sandra is quite fit as she has been seen exercising with a fitness ball while Carl has gone out to pick up a new grow lamp.

Baz-El (voiced by Rob Paulsen) is a Galvanic Mechamorph and Ship's father. Baz-El later loses custody of Ship, who decides to stay with Julie after learning of Baz-El's intentions to use him as a weapon.

Verdona (voiced by Juliet Landau in her Anodite form, Barbara Bain in her human form) is Ben and Gwen's paternal grandmother. She is an Anodite who Gwen inherited the ability to control and manipulation of mana, the substance of magic and life itself. Verdona initially met Max Tennyson in the 1960s after being brought to Earth by a Synthroid, a robotic alien who intended to use her to power his world. After escaping from the Synthroid, Verdona landed in St. Louis, where she met and fell in love with Max after he saved her; they then courted each other and married. During this time she hid her Anodite heritage very well and blended in with society. During their time together, Verdona hid from Max that she knew about his occupation as a Plumber, prompting Max to always lie to her every time he left. Eventually after a long, happy and yet somewhat distant relationship, they parted.

Frank Tennyson (voiced by George Newbern) is Gwen's father.

Natalie Tennyson (voiced by Juliet Landau) is Gwen's mother.

Reinrassig III (voiced by Richard McGonagle) is a Highbreed officer who Ben is forced to work with while they are both trapped on the desert planet Turrawuste. Reinrassig loses his right hand saving Ben from a Rodilla Dentia, but Ben uses Swampfire to reattach it. The vine Ben used to reattach his arm eventually spreads to cover Reinrassig's entire lower arm, which alters his DNA. This causes him to be unaffected by Ben rewriting the genetic code of the other Highbreed. The Highbreed are horrified at Ben's actions, but Reinrassig explains to them that Ben meant to save them from extinction. This causes the Highbreed Council to elect him as the new Highbreed Supreme, the leader of all Highbreed.

Elena Valadis (portrayed by Alyssa Diaz in Alien Swarm, voiced by Tia Texada in Ultimate Alien) is the daughter of former plumber Victor Valadis. She eventually discovers her father had been taken over by the Hive Queen and seeks help from Ben and the Plumbers. As Nanomech, Ben kills the Queen, who controlled the Nanochips.

Elena returns in the Ultimate Alien episode "Revenge of the Swarm", where she is possessed by the remaining Nanochips. After nearly killing Ben, Elena eventually regains control of her body long enough to seemingly commit suicide by walking directly into a Nanochip-destroying force-shield that she had developed. Elena is later revealed to have survived, having returned to villainy.

Victor Valadis (portrayed by Herbert Sigüenza in Alien Swarm, voiced by Brian George in Ultimate Alien) is a former Plumber and Elena's father.

Colonel Rozum (voiced by John DiMaggio) is an Air Force officer and a colleague of Max Tennyson.

The Unitrix (voiced by Molly C. Quinn) is a prototype version of the Omnitrix that obtains a human form after absorbing Gwen's DNA and altering it to create a unique body. It is capable of storing DNA of different species, but is not connected to the Codon Stream or Primus, limiting it to a single DNA sample. Eunice was also shown to be able to absorb DNA and powers of several animals and then to manifest traits of these animals without changing form. In addition, local wildlife seems to be attracted to her to the point where normally shy animals gather around her and more dangerous animals are rendered docile.

Ignacius Baumann (voiced by Richard Doyle in Ultimate Alien, Corey Burton in Omniverse) is a storekeeper who sells alien provisions. He is the subject of a running gag where Ben accidentally destroys his businesses. In the Omniverse episode "The Ballad of Mr. Baumann", Baumann marries Sheelane, a mermaid-like alien.

Zed (vocal effects provided by Paul Eiding) is an Anubian Baskurr and Khyber's former hunting dog, who Kevin adopts after Khyber abandons her. She formerly wielded the Nemetrix, an Omnitrix-like device that enabled her to transform into various predatory species. In the fourth season of Omniverse, Albedo upgrades the Nemetrix with an evolutionary feature similar to the Ultimatrix.

• Buglizard is a lizard-like alien and Stinkfly's predator. It has enhanced agility and sense of smell and can generate fog that melts Stinkfly's slime.
• Crabdozer is a rhinoceros/crab-like alien and Heatblast's predator. It has immense strength and fireproof rock-like skin.
• Hypnotick is a moth-like alien and Big Chill's predator. It is immune to intense cold and can become intangible and generate hypnotic mist that forces others to see visions of their greatest desires.
• Mucilator is a frog-like alien and Crashhopper's predator. It has immense strength and durability as well as adhesive sacs across its body.
• Omnivoracious is a ratite-like alien and Gray Matter's predator. It is highly intelligent, leading Galvans to be unable to outwit it. The Omnivoracious species became extinct long ago following a meteor strike, with Khyber obtaining Omnivoracious DNA from a fossil.
• Panuncian is a Smilodon-like alien and Ditto's predator. It is highly agile and possesses similar duplication abilities to its prey. Panuncian's Ultimate form is larger and possesses spiked armor. In the fourth season of Omniverse, Khyber obtains a Panuncian to act as a hunting dog after Zed abandons him.
• Slamworm is a worm-like alien and Armodrillo's predator. It can dig at high speeds and possesses acidic saliva and a sharp beak, both of which are adapted to destroy Talpaedan armor.
• Terroranchula is a tarantula-like alien and Ball Weevil's predator. It has sharp, powerful legs and can generate energy webs that destroy Insectoid slime.
• Tyrannopede is a dinosaur/insect-like alien and Humungousaur's predator. It has immense strength and durability and can generate webbing from its horn.
• Vicetopus is an octopus-like alien and Brainstorm's predator. It has a rubbery body that makes it elastic and resistant to electricity.

Pakmar (voiced by Tara Strong) is an alien shopkeeper who resides in Undertown. He is the subject of a running gag where Ben accidentally destroys his businesses.

Blarney Hokestar (voiced by Charlie Adler) is an alien con artist and smoothie seller.

Pax (voiced by Eric Bauza) is a Florauna animal lover and alien rights activist. His love for wildlife, especially dangerous animals, places himself and others in danger on a regular basis.

The Kraaho are hot-blooded tungsten-based aliens who thrive in warm temperatures, specifically environments higher than 100 degrees.

Seebik (voiced by Corey Burton) is a thief and the former leader of the Kraaho.

Ester (voiced by Tara Platt) is a half-Kraaho who helps Ben stop Seebik and the Kraaho from bringing the magma up from the Earth. Afterwards, Seebik made Ester the new leader of the Kraaho. According to Ester, the Kraaho will now live in peace with both Bellwood and Undertown. Ester goes on to have an intermittent relationship with Ben until they break up in the episode "The Most Dangerous Game Show".

Hobble (voiced by Steve Blum) is an insect-like alien and a member of the Plumbers' Alpha Squad. His diminutive size is accompanied by poor physical abilities, with his species' main advantage being a protective layer of mucus secreted by their skin.

Rad Dudesman (voiced by Carlos Alazraqui) is a duck-like alien mercenary. He is skilled at the use of advanced weaponry and pilots a spaceship called the Lovely Duck. Rad is occasionally employed by the Plumbers to carry cargo and passengers, and has thus met and worked with Ben on a number of occasions.

Pyxi (voiced by Carlos Alazraqui) is Rad's AI assistant.

Scout (voiced by Carlos Alazraqui) is a Loboan Plumber stationed in the Anur System.

Skurd (voiced by David Kaye) is a Slime-biot, a squid-like alien who can manipulate DNA. When attached to an alien, he can feed on the alien DNA and can grow his host's body parts from himself. When attached to the Nemetrix or Omnitrix, Skurd can grow the body parts of an alien and use it as an armor by spreading to their respective body parts and then shifting into another alien's limb or something based on another alien. After the defeat of Maltruant, Skurd learns that the Slime-biots were created by the ancient race known as the Contemelia to spread DNA across the universe and parts ways from Ben to rejoin his people.

Heatblast (voiced by Steve Blum in the original series, David Franklin in Race Against Time, Dee Bradley Baker in Ultimate Alien, David Kaye in Omniverse, Daryl Sabara in the reboot) is a Pyronite, a fiery rock-based alien from the planet Pyros. He can generate and manipulate fire and fly by levitating rock. In the original series, Heatblast is Ben's first alien transformation; Ben accidentally transformed into Heatblast in the first episode of the original series, “And Then There Were 10”, after trying to remove the Omnitrix when it first attached to him.

WIldmutt (voiced by Dee Bradley Baker) is a Vulpimancer, a dog-like alien from the planet Vulpin. He is blind and incapable of speech, but has enhanced senses, including smell and hearing. Wildmutt's porcupine-like quills supplement his sonar and can be used as projectiles or protect him while he is rolling. This ability is unique to adult Vulpimancers, and as Ben's version is only sixteen years old, these quills have not fully developed. However, in the future shown in "Ben 10,000" and "Ken 10”, he is fully grown and possesses the abilities of adult Vulpimancers. Ultimate Wildmutt (also voiced by Dee Bradley Baker) is red and capable of speech.

Diamondhead (voiced by Jim Ward in the original series, Daran Norris in Race Against Time, Dee Bradley Baker in Alien Force and Ultimate Alien, Eric Bauza in Omniverse, Roger Craig Smith in the reboot) is a Petrosapien, a humanoid silicon-based alien from the planet Petropia. Diamondhead can control his crystal physiology at will, allowing him to create crude crystal weapons, fire crystal shards from his hands, and regenerate his body. However, Diamondhead's crystal can shatter if exposed to strong sonic vibrations.

XLR8 (voiced by Jim Ward in the original series, Yuri Lowenthal in Omniverse, Josh Keaton in the reboot) is a Kineceleran, a raptor-like alien from the planet Kinet. He can manipulate his own friction to move faster than lightning, climb up walls, run on water, easily come to a dead stop on most surfaces, and create tornadoes by running in a small circle or spinning.

Grey Matter (voiced by Richard Steven Horvitz in the original series, Carlos Alazraqui in Race Against Time, Eric Bauza in Omniverse, Todd Haberkorn in the reboot) is a Galvan, a small frog-like alien from the planet Galvan Prime. Grey Matter possesses an advanced intellect that allows him to outwit larger enemies, create almost anything from spare parts, and deduce the function of any device at a glance. Grey Matter's size allows him to squeeze into small spaces and climb walls due to tiny suction cups on his skin.

Four Arms (voiced by Richard McGonagle in the original series, Dee Bradley Baker in Ultimate Alien, John DiMaggio in Omniverse and the reboot) is a Tetramand, a red four-armed alien from the planet Khoros. He has an extremely dense musculature, making him unmatched in pure physical strength; however, he is slow and unable to use things normally used by smaller creatures. Using Four Arms' strength, Ben can create shock waves by pounding the ground or clapping all four of his hands together, and his leg strength allows him to cross entire city blocks in a single jump.

Stinkfly (voiced by Dee Bradley Baker in the classic continuity, Greg Cipes in the reboot) is a Lepidopterran, a quadrupedal insect-like alien from the planet Lepidopterra. He can fly at high speeds and generate adhesive slime with various properties. If Stinkfly's wings get wet, he will be unable to fly. In the reboot, Stinkfly is redesigned to resemble a humanoid blue dragonfly.

Ripjaws (voiced by Fred Tatasciore in the original series, Eric Bauza in Omniverse) is a Piscciss Volann, a fish-like alien from Piscciss, a world made of 98% water with solid matter only at its core. Piscciss Volanns have many variations but share a luminescent dangle and an ability to withstand increased amounts of pressure and swim at great speeds. They are also voracious eaters, able to unhinge their jaws to bite into much larger objects and even rip through steel. However, Ripjaws is incapable of surviving for long outside water.

Upgrade (voiced by Tara Strong in the original series, Yuri Lowenthal in Heroes United and Omniverse, David Sobolov in the reboot) is a Galvanic Mechamorph, a race that was accidentally created by Galvan scientists who tried to make Galvan B (their planet Galvan Prime's moon) habitable by binding self-replicating nanotechnology to Galvan B's minerals. When a new sentient species was born as a result, the Galvans abandoned the project and allowed the Galvanic Mechamorphs to flourish on their own. Other than firing plasma beams from its eye, a Galvanic Mechamorph's primary ability is to merge with technology, upgrading or changing it far beyond its original design. While they can control non-sentient machines, Galvanic Mechamorphs are incapable of properly controlling sentient technology. Galvanic Mechomorphs are also vulnerable to electricity and any substance corrosive to regular metals, both of which can damage their delicate innards.

Ghostfreak (voiced by Steve Blum in the original series and Omniverse, Jeff Bennett in Alien Force and Ultimate Alien) is an Ectonurite, a one-eyed ghost-like creature from the planet Anur Phaetos. Ectonurites normally have a protective skin that condenses their form to resemble ghosts, their eye moving along a black track on that skin. Ectonurites can phase through matter, possess people, turn invisible and fly. They are stronger in darkness and can be weakened in sunlight to the point of death by combustion. Ghostfreak was sampled from Zs'Skayr, an evil Ectonurite whose consciousness was added to the Omnitrix alongside his genetic sample. Zs'Skayr was subsequently trapped in the Omnitrix before escaping in the episode "Ghostfreaked Out".

Cannonbolt (voiced by Fred Tatasciore in the original series, Dee Bradley Baker in Alien Force and Ultimate Alien, David Kaye in Omniverse, Travis Willingham in the reboot) is an Arburian Pelarota, a hulking, broad-shouldered alien covered in natural armor plating. By curling up into a ball, he can encase himself in his armor, becoming virtually invulnerable. The drawback is that Cannonbolt quickly picks up momentum, which can make hitting more agile targets difficult, as he cannot slow down quickly; in addition, Cannonbolt's speed and maneuverability is limited outside of his ball form, owing to his bulk and high center of gravity. Ultimate Cannonbolt (also voiced by Dee Bradley Baker) has a gray shell covered in spikes that he can shoot as projectiles.

Wildvine (voiced by Jim Ward in the original series, Dee Bradley Baker in Omniverse, David Hornsby in the reboot) is a Florauna from the planet Flors Verdance. Florauna are plant-based aliens with tentacle-like roots for legs, and carnivorous plant-shaped flaps covering their heads. Among a Florauna's abilities are extending limbs, thorns, generating explosive seeds, merging with other plants, and regenerating from near fatal attacks. In the reboot, Wildvine is redesigned to be bipedal.

Spitter (voiced by Dee Bradley Baker) is a Sphoeroid, a pufferfish-like alien from the planet Scalpasc. He can generate massive amounts of slime from his mouth.

Buzzshock (voiced by Tara Strong in the original series and reboot, Eric Bauza in Omniverse) is a Nosedeenian, a battery-like alien from the Nosideen Quasar. Commonly referred to as Megawhatts, Nosedeenians are battery-like energy beings who can manipulate electricity, travel through any electrical source at high speeds, and reproduce via mitosis once they gather enough energy.

Arctiguana (voiced by Tom Kane in the original series, Eric Bauza in Omniverse) is a Polar Manzardill, a lizard-like alien from the planet X'Nelli. Arctiguana can fire a long-range freeze ray that can freeze targets in ice, freeze molten lava, and create an icy path that he can skate across in a snowboard-like fashion. Arctiguana can survive in sub-freezing temperatures and breathe underwater. Arctiguana's Ultimate form (also voiced by Eric Bauza), used by Albedo, is larger and possesses shoulder-mounted ice cannons.

Blitzwolfer (voiced by Tara Strong in the original series, Kevin Michael Richardson in Omniverse) is a Loboan, a bipedal wolf-like alien from the moon Luna Lobo. He has enhanced physical abilities and can generate sonic howls by splitting his jaw. He was originally named Benwolf before being renamed in Omniverse.

Snare-oh (voiced by Richard Green in the original series, Kevin Michael Richardson in Omniverse) is a Thep Khufan, a mummy-like alien from the planet Anur Khufos. His body is made of elastic bandages, enabling him to stretch and disassemble his body at will. Snare-oh was originally named Benmummy before being renamed in Omniverse.

Frankenstrike (voiced by Michael Dorn in the original series, David Kaye in Omniverse) is a Transylian, a Frankenstein monster-like alien from the planet Anur Transyl. He can generate electricity, adhere to metal surfaces through electromagnetism, and survive in the vacuum of space. Frankenstrike was originally named Benvicktor before being renamed in Omniverse.

Upchuck (voiced by Dave Wittenberg in the original series, Dee Bradley Baker in Alien Force and Ultimate Alien, Eric Bauza in Omniverse) is a Gourmand, a reptilian alien from the planet Peptos XII. Gourmands are small frog-like aliens with a very large appetite, their four adhesive tongues stretching out to latch onto large objects and swallow whole. As Gourmand's mouths and stomachs stretch to facilitate the digestion, the latter converts the ingested matter into explosive balls of liquid that can be expelled at will.

Ditto (voiced by Rob Paulsen) is a Splixson, a mole-like alien from the planet Hathor. He can clone himself limitlessly, but each clone shares pain with the other clones; the death of one clone will cause the death of the rest. If a clone is separated from the others during the Omnitrix's timeout phase, Ben is forced to remain stuck as Ditto until the copies are brought sufficiently close together.

Eye Guy (voiced by Dee Bradley Baker in the original series, Paul Eiding in Omniverse) is an Opticoid, a humanoid boneless alien from the planet Sightra. Eye Guy's upper body is covered in eyes, though he has no eyes on his head. From these eyes, Eye Guy can fire numerous energy beams such as ice beams, fire beams, and laser beams.

Way Big (voiced by Fred Tatasciore in the original series, Dee Bradley Baker in Alien Force and Ultimate Alien, Eric Bauza in Omniverse, Roger Craig Smith in the reboot) is a To'kustar, a colossal humanoid alien that has no home planet and is born in cosmic storms. He has immense strength and can generate cosmic energy beams. His Ultimate form (also voiced by Dee Bradley Baker) has increased size and a red and blue color scheme, often regarded as an homage to Ultraman.

Eon (portrayed by Christien Anholt) is a Chronian, a humanoid alien from the planet Chronia. Eon forces Ben to transform into a Chronian to power the Hands of Armageddon.

Swampfire (voiced by Dee Bradley Baker) is a Methanosian, a plant-like humanoid from the planet Methanos. Besides being able to control plant life and producing seeds that quickly grow into vines, Swampfire also has a vast regenerative ability that allows him to regenerate lost limbs. In Omniverse, Swampfire undergoes a puberty-like process, gaining enhanced abilities and a red and yellow color scheme.

Ultimate Swampfire (also voiced by Dee Bradley Baker) resembles a tree and has blue napalm-like sacs across his body.

Echo Echo (voiced by Dee Bradley Baker) is a Sonorosian, a robot-like alien from the planet Sonorosia. He can scream at ultrasonic frequencies, capable of overloading machinery and stopping projectiles in mid-flight; he can also use echolocation; and channel vibrations to enhance his power and transmit sound waves through speakers. Echo Echo can duplicate himself, but unlike Ditto, the clones are not linked in any way and can revert to human form even if all duplicates are not re-integrated. His Ultimate form (also voiced by Dee Bradley Baker) has the ability to fly and wields sonic discs that amplify his sound blasts, but is unable to duplicate.

Humungousaur (voiced by Dee Bradley Baker in Alien Force and Ultimate Alien, John DiMaggio in Omniverse, David Kaye in the reboot) is a Vaxasaurian, a dinosaur-like alien from the planet Terradino. He has immense size and strength and can grow further, up to a maximum of 60 feet. Ultimate Humungousaur (voiced by Baker in Alien Force and Ultimate Alien and DiMaggio in Omniverse) is green, has a spiked shell, and can shoot bony bullets from his hands.

Jetray (voiced by Dee Bradley Baker) is an Aerophibian, a manta ray-like alien from the planet Aeropela. He can fly and swim at supersonic speeds, accelerate to speeds greater than light, and shoot energy blasts called neuroshocks through his eyes and tail. Jetray does not need to breathe, enabling him to easily travel through water and space.

Big Chill (voiced by Dee Bradley Baker) is a Necrofriggian, a moth-like alien from the planet Kylmyys. He can become intangible and freeze an opponent in various ways, one of which utilizes intangibility to freeze anything that he passes through. However, Big Chill can be harmed by opponents who are also intangible, with their abilities cancelling each other out. His Ultimate form (also voiced by Dee Bradley Baker) is red and can generate plasma beams.

Chromastone (voiced by Dee Bradley Baker in Alien Force, Ultimate Alien, and the reboot, Eric Bauza in Omniverse) is a Crystalsapien, a humanoid crystal-based alien from the planet Petropia. Crystalsapiens are a unique species with only one member, Sugilite, who protects Petropia. Chromastone can absorb most kinds of energy and channel it into multicolored laser blasts.

Brainstorm (voiced by Dee Bradley Baker in Alien Force and Ultimate Alien, Corey Burton in Omniverse) is a Cerebrocrustacean, a crab-like alien from the planet Encephalonus IV. He possesses advanced intelligence, which allows him to perform complex calculations, and can generate electrical blasts from his pincers and brain. Brainstorm can also levitate and create force fields

Spidermonkey (voiced by Dee Bradley Baker) is an Arachnichimp, an alien from the planet Aranhascimmia who resembles a monkey with multiple arms and eyes. He is highly agile and can generate large amounts of webbing from his tail. Ultimate Spidermonkey (voiced by Baker in Ultimate Alien and Paul Eiding in Omniverse) resembles a large purple gorilla with spider legs and can generate webs from his mouth.

Goop (voiced by Dee Bradley Baker) is a Viscosian, a humanoid slime-based alien from an unidentified planet. He has a malleable, slime-like body with shapeshifting capabilities and can generate acid. Goop utilizes an anti-gravity generator resembling a small flying saucer that allows him to retain mobility in Earth and other environments that have higher gravity that his home planet.

Alien X (voiced by Yuri Lowenthal in the classic continuity, Fred Tatasciore in the reboot) is a Celestialsapien, a humanoid alien from the Forge of Creation, a region outside the universe. Alien X has vast reality-warping abilities coupled with two split personalities: Bellicus (voiced by Kevin Conroy in Alien Force, Jeff Bennett in Alien Force: Vilgax Attacks and Ultimate Alien, and Eric Bauza in Omniverse) and Serena (voiced by Vicki Lewis in Alien Force, Tara Strong in Ultimate Alien, and Kimberly Brooks in Omniverse), who prevent him from acting until Ben convinces them to. Theoretically, Alien X possesses limitless power, as any thought Alien X conceives can be transformed into reality if all split personalities agree.

Lodestar (voiced by Dee Bradley Baker) is a Biotsavartian, a humanoid metallic alien from the planet Maxwell. He has magnetic powers, being able to create magnetic fields, enabling him to emit magnetic pulses, and control metallic objects; he can also regenerate, create protective barriers, and fly.

Rath (voiced by John DiMaggio in the classic continuity, Dee Bradley Baker in the reboot, and Bill Rogers in the video game Ben 10: Power Trip) is an Appoplexian, a tiger-like alien from the planet Appoplexia. He has immense strength and durability coupled with uncontrollable aggression. Ultimate Rath (also voiced by John DiMaggio), used by Albedo, is larger and inspired by Marvel Comics character Kraven the Hunter.

Nanomech (voiced by Alex Winter in Alien Swarm, Dee Bradley Baker in Ultimate Alien and Omniverse) is a Microchip that was uniquely created by the Omnitrix. Unlike other Microchips, he has a humanoid, insect-like body due to being half-human and half-microchip. Nanomech can shrink to microscopic sizes and generate energy blasts from his eyes and hands.

Waterhazard (voiced by Dee Bradley Baker) is an Orishan, a mollusc-like alien from the planet Kiusana. He can manipulate pre-existing water, expel it as pressurized blasts, and fly by using water as propulsion.

Ampfibian (voiced by Dee Bradley Baker in Ultimate Alien and the reboot, Yuri Lowenthal in Omniverse) is an Amperi, a jellyfish-like alien from the planet Tesslos. He can generate electricity from his tentacles; sense the electrical pulses in the minds of other life forms, allowing him to read their thoughts; turn intangible; and absorb and redirect energy. AmpFibian can also travel through air, water, and electronic currents by turning his body into electricity.

Armodrillo (voiced by Dee Bradley Baker in Ultimate Alien, John DiMaggio in Omniverse) is a Talpaedan, an armadillo-like alien from the planet Poiana Lüncas. He has two jackhammer-like arms that give him the ability to drill into the ground, or form jackhammers or drills.

Terraspin (voiced by Dee Bradley Baker in Ultimate Alien, Bumper Robinson in Omniverse) is a Geochelone Aerios, a turtle-like alien from the planet Aldabra. Terraspin has the ability to retract his head into his shell, where an opening in the shell serves as a viewfinder; in this state, he can blow wind from the holes in its shell while also using his arms as propellers.

NRG (voiced by Dee Bradley Baker) is a Prypiatosian-B, an energy-based alien from the planet Prypiatos. NRG is a radioactive energy being encased within an oven-like invulnerable containment suit that contains his radiation. When released, he can shoot energy beams, create intense heat, and become intangible, so he cannot be touched except by the material his armor is made of.

Fasttrack (voiced by Dee Bradley Baker) is a Citrakayah, a humanoid cat-like alien from the planet Chalybeas. He can move at superhuman speeds, similar to XLR8.

Chamalien (voiced by Dee Bradley Baker) is a Merlinisapien, a chameleon-like alien from an unidentified planet. He can change color to camouflage himself with only his shadow visible. He can also grow a spike out of the end of his tail; in addition he is very agile and can stick to surfaces with his great physical adherence.

Eatle (voiced by Dee Bradley Baker in Ultimate Alien, Eric Bauza in Omniverse) is an Oryctini, a beetle-like alien from the planet Coleop Terra. Similar to Upchuck, Eatle is able to ingest all sorts of different material and convert it into energy beams.

Clockwork (voiced by Dee Bradley Baker) is a Chronosapien, a robotic alien from an unidentified planet. Capable of traveling through time and space, Chronosapiens can produce time rays that can either age or regress their targets or slow everything down around them. They can display events that have happened in the past by rotating the keys on their heads, which creates holographic images of past actions.

Juryrigg (voiced by Dee Bradley Baker in Ultimate Alien, Bumper Robinson in Omniverse) is a Planchaküle, a gremlin-like alien from the planet Aul-Turrhen. He has innate engineering abilities and can disassemble and reassemble machinery into new forms. In Omniverse, Jury Rigg wears an aviator's suit, which includes goggles and a scarf.

Shocksquatch (voiced by David Kaye) is a Gimlinopithecus, a yeti-like alien from the planet Pattersonea. He can generate and manipulate electricity, enabling him to shield himself from radiation.

Feedback (voiced by Yuri Lowenthal) is a Conductoid, a black humanoid alien from the Teslavorr Nebula. He has plug-like fingers and long antennae that enable him to absorb and redirect energy. Feedback was Ben's favorite alien when he was 11 years old, until Malware destroyed Feedback and removed him from the Omnitrix. However, in the episode "Showdown", Ben regained the ability to turn into Feedback.

Bloxx (voiced by Bumper Robinson in Omniverse, David Kaye in the reboot) is a Segmentasapien, a primate-like alien from the planet Polyominus. He has an elastic body made of Lego-like bricks that can form various constructs and be shot as projeciles. He can alter his body structure into any form needed and regenerate; however, his body is fragile and is easily broken when hit with enough force.

Gravattack (voiced by David Kaye) is a Galilean, a living planetoid alien from the planet Keplorr. Gravattack can manipulate the gravity of himself and others, changing their mass, making them heavier or lighter. Also with his gravity manipulation, he can make objects orbit around him like a planet. Ultimate Gravattack (also voiced by David Kaye), used by Albedo, has three smaller planetoids orbiting him and lacks legs.

Crashhopper (voiced by Dee Bradley Baker) is an Orthopterran, a grasshopper-like alien from an unidentified planet. He has powerful legs that enable him to jump far and create shockwaves upon landing. He also possesses a resistant skull, which is used to hit with great impact.

Ball Weevil (voiced by Bumper Robinson) is an Insectoid, an insect-like alien from the planet Atrocious 0. He can generate adhesive balls of slime that can absorb matter and grow in size. These spheres either explode on impact or can be detonated manually.

Walkatrout (voiced by Yuri Lowenthal) is an Ickthyperambuloid, a fish-like alien from the planet Gilli-Perambulous Promenade. He is physically weak, with his only power being slippery skin that makes him agile and difficult to grab.

Pesky Dust (voiced by Tara Strong) is a Nemuina, a fairy-like alien from the planet Nemuinos IV. He can fly and generate dust that enables him to put others to sleep and manipulate dreams.

Mole-Stache (voiced by David Kaye) is an unidentified mole-like alien from an unidentified planet. He has a prehensile mustache that can act as fists and enables him to fly by spinning like a helicopter.

The Worst (voiced by Dee Bradley Baker) is an Atrocian, a rotund alien from the planet Atrocian. He is highly durable and virtually indestructible, but is not immune to pain.

Kickin Hawk (voiced by Yuri Lowenthal) is an unidentified bird-like alien from an unidentified planet. He is highly skilled in hand-to-hand combat and has sharp blades on his elbows.

Toepick (voiced by Eric Bauza) is an unidentified ogre-like alien from an unidentified planet. He has a terrifying face that can incapacitate others, which is usually covered by a cage-like helmet.

Astrodactyl (voiced by Dee Bradley Baker) is an unidentified Pterosaur-like alien from an unidentified planet. He is able to fly at high speeds and can generate and manipulate stellar energy.

Bullfrag (voiced by John DiMaggio) is an Incursean, a frog-like alien from an unidentified destroyed planet. He is highly agile and has a prehensile tongue. Bullfrag is extremely sensitive to strong odors.

Atomix (voiced by John DiMaggio) is an unidentified robotic alien from an unidentified planet. He has immense strength and can generate atomic blasts and orbs of atomic energy.

Gutrot (voiced by Rob Paulsen) is an unidentified robotic alien from an unidentified planet. Gutrot is able to mix and generate gas from inside his body, which has a large, transparent stomach that leaves the gas visible.

Whampire (voiced by John DiMaggio) is a Vladat, a vampire-like alien from the planet Anur Vladias. He can drain the life force of others and use hypnosis and bat-like parasites called Corrupturas to control his opponents mentally and physically.

Overflow (voiced by Max Mittelman) is a Cascan, a water-based alien from the planet Cascareau. He has a similar appearance and powers to Waterhazard.

Gax (voiced by Yuri Lowenthal) is a Chimera Sui Generis, a squid-like alien of the same species as Vilgax. Ben loses access to Gax after Vilgax steals his DNA to regain his full strength.

Shock Rock (voiced by David Kaye) is a Fulmini, an energy-based alien from the destroyed planet Fulmas. He can generate and manipulate electricity. Shock Rock's presence in the Omnitrix influences the other Omnitrix aliens and gives them additional electricity-based abilities similar to his.

Slapback (voiced by Todd Haberkorn) is an Ekoplektoid, a frog-like alien from the planet Ekoplekton. He can duplicate when struck on the back, with clones progressively gaining increased strength and density.

Surge (voiced by Fred Tatasciore) is a Xerge, a robotic X-shaped alien from an unidentified planet. He is powerless on his own, but can link with other Xerge to create constructs.

Vilgax (voiced by Steve Blum in the original series and Omniverse, James Remar in Alien Force and Ultimate Alien, Yuri Lowenthal in the reboot) is a Chimera Sui Generis warlord who is Ben's first and most recurring nemesis through the series. Vilgax was exiled from his home world for being ruthless, cruel, and power hungry. Soon after, Vilgax learned of the Omnitrix's existence after being attacked by George Washington and a mysterious figure later revealed to be a time-traveling Ben. Vilgax became determined to have the Omnitrix and use it to build an army for his use.

Aloysius Animo (voiced by Dwight Schultz) is a brilliant mad scientist obsessed with genetic experiments on animals, and Ben's first human enemy. He was once a promising researcher in veterinary science that had a special way with animals, but his career was cut short when it was discovered that he was performing twisted genetic experiments on animals. He had hoped that his research would win him the Verties Award in veterinary science, but the revelation resulted with the award given to another doctor named Kelly. This drove Animo insane as he dropped off the map for five years until he could perfect his research.

SixSix (voiced by Dee Bradley Baker in the original series, Josh Keaton in the reboot) is a bounty hunter and mercenary from the Sotoragg system. Sixsix's armor is covered with pouches that hold various weapons and projectiles. He also has multiple small claws and hands that extend from his shoulders that are usually used to throw the small pikes coming out of his jet pack, or bombs when he is using his blasters.

Kraab (voiced by Billy West in the original series, Jeff Bennett in Alien Force, Dee Bradley Baker in Omniverse, Travis Willingham in the reboot) is a Piscciss Premann cyborg and bounty hunter. In the original series' pop-up trivia, it is established that Kraab is a veteran of a war with Pyros that resulted in 95% of his body being destroyed and replaced with mechanical parts.

Rojo (voiced by Jennifer Hale in the original series and Omniverse, Kari Wahlgren in Ultimate Alien) is a thief and gang leader. In the original series, she temporarily fuses with one of Vilgax's drones, which gives her the ability to fly, metallic claws, and a pair of blasters attached to each shoulder. Vilgax was able to communicate with her through the parts and force her to track down the Omnitrix for him. Rojo is turned back to normal when Upgrade shorts out her armor.

Zombozo (voiced by John Kassir in the original series, John DiMaggio in subsequent appearances) is a zombie-like clown who feeds on fear. In his initial appearance, Zombozo instead fed on happiness and life energy.

The Circus Freak Trio are a trio who worked together under the guise of freak show performers in Zombozo's circus before his disappearance.

Acid Breath (voiced by Dee Bradley Baker in the classic continuity, Josh Keaton in the reboot) is a member of the Circus Freaks who can project corrosive acid from his mouth.

Frightwig (voiced by Cree Summer in the classic continuity, Jessica DiCicco in the reboot) is a member of the Circus Freaks who has prehensile, tentacle-like hair.

Thumbskull (voiced by Jeff Doucette in the original series, David Kaye in Omniverse, John DiMaggio in the reboot) is a member of the Circus Freaks who has superhuman strength and a nail-like horn.

Hex (voiced by Khary Payton in the classic continuity, Robin Atkin Downes in the reboot) is a sorcerer from Ledgerdomain and Charmcaster's uncle. He possesses five magical mystic charms called the "Charms of Bezel" that give him incredible mystical powers and abilities, in addition to his own spell-casting abilities. In Omniverse, he reforms and becomes a professor at Friedkin University.

Phil Billings (voiced by Robert Patrick in the original series, Rob Paulsen in Omniverse, John DiMaggio in the reboot) is a corrupt former Plumber and partner of Max. In between the events of the original series and Omniverse, Khyber and Dr. Psychobos use Billings as a test subject for the Nemetrix, giving him the ability to transform into a Terroranchula hybrid. Unbeknownst to Khyber and Psychobos, the Nemetrix is not compatible with sentient beings, which resulted in Billings's mind being destroyed and replaced with a monstrous alternate persona.

In the reboot, Billings is a benevolent inventor who remains a member of the Plumbers.

The Forever Knights are a secret paramilitary organization dealing with alien encounters and other varying activities. They were founded by Sir George to fight Dagon, but his departure resulted in them splintering into factions, each led by a Forever King. During the events of Ultimate Alien, George reunites the Forever Knights to combat Dagon, during which most of them are killed.

The Forever Knights consist of Enoch (voiced by Richard Doyle), Driscoll (voiced by Richard Doyle), the Red Knight, Connor (voiced by Hakeem Kae-Kazim), Joseph Chadwick (voiced primarily by Tim Curry and by David Kaye in the Omniverse episode "Return to Forever"), Morton (voiced by Kevin Michael Richardson), Winston (voiced by Patrick Cavanaugh), Urian (voiced by Jim Piddock), and Cyrus (voiced by Robin Atkin Downes).

In the reboot, a lone Forever Knight (voiced by Roger Craig Smith) is featured as a major antagonist.

Clancy (voiced by Nicholas Guest) is a mutant human who can control insects. He later resurfaces as a member of the Negative 10, having mutated into an insectoid creature with the ability to emit wasps from his mouth.

Vulkanus (voiced by John DiMaggio) is a Detrovite criminal. His body was previously destroyed in an explosion, leaving only his head intact and forcing him to wear powered armor until his body regenerated.

Charmcaster (voiced by Kari Wahlgren in the classic continuity, Tara Strong in the reboot) is a sorceress from Ledgerdomain and Hex's niece. Her father Spellbinder was previously killed by Addwaitya, forcing her and Hex to flee to Earth. She carries a magic satchel from which she can draw all manner of items, such as magical explosives, throwing blades, or even various clay animals to enlarge and animate. Charmcaster is often the victim of emotionally based abuse at the hands of her uncle and it is also heavily implied he abuses her even physically. This abuse strongly explains her egocentric and adversarial nature with the Tennyson family, especially Gwen.

Zs'Skayr (voiced by Steve Blum in the original series and Omniverse, Jeff Bennett in Alien Force) is the leader of Anur Phaetos and Ghostfreak's genetic donor. Zs'Skayr learned about the Omnitrix from one of Vilgax's drones, tricking Myaxx into allowing him to accompany her in acquiring a sample of Florauna DNA. However, possessing the donor, Zs'Skayr manages to have his DNA scanned with the Florauna's for the Omnitrix. Zs'Skayr eventually manages to escape from the Omnitrix, which restores his body.

The Werewolf is an unnamed Loboan and a servant of Zs'Skayr. It is initially mistaken for a Yenaldooshi, a werewolf-like creature originating from Navajo folklore.

The Mummy is an unnamed Thep Khufan and a servant of Zs'Skayr.

Dr. Viktor (voiced by Michael Dorn) is a Transylian scientist and Zs'Skayr's assistant. In Omniverse, Viktor helps Zs'Skayr drain all the energy of the Alpha Rune in what he saw to be madness in reviving Lord Transyl. When he learns that Zs'Skayr intends to revive the entire Vladat race, who treated the Transylians as slaves during their reign, Viktor briefly works with Ben to stop Zs'Skayr and Lord Transyl.

Exo-Skull (voiced by Richard McGonagle in the original series, David Kaye in Omniverse) is a rhinoceros-like mutant created by Dr. Animo. Originally encountered in Ben 10,000's future in the original series, a present-day version of Exo-Skull is later seen in Omniverse as one of Maltruant's minions and the partner of Subdora.

Kane North (voiced by John Cygan in the original series, Corey Burton in Omniverse) is the creator of the television series Kangaroo Kommando and a criminal who wields a suit based on the series' eponymous character.

Eon (portrayed by Christien Anholt in Race Against Time, voiced by Yuri Lowenthal and Sean Donnellan in Ultimate Alien, Judd Nelson in Omniverse) is a time-travelling villain and rival of Professor Paradox. In Race Against Time, Eon is initially depicted as a Chronian, a humanoid alien, who seeks to invade Earth using the Hands of Armageddon. In later appearances, it is retconned that the events of Race Against Time took place in an alternate timeline. A new version of Eon is introduced who is an alternate universe version of Ben Tennyson.

Eon's Servants are the servants of Eon. They are depicted as corrupted alternate timeline versions of Ben in the original series and Ultimate Alien and as robots in Omniverse.

The Atasians, commonly known as the Highbreed, are a xenophobic species from the planet Augstaka who serve as the initial primary antagonists of Alien Force. They are voiced by various actors, including Dee Bradley Baker, Paul Eiding, Robert David Hall, Richard McGonagle, and Kevin Michael Richardson.

The DNAliens are lifeforms infected by Xenocites, parasitic aliens created by the Highbreed. They are voiced by various actors, including Dee Bradley Baker, Jeff Bennett, Greg Cipes, Diane Delano, Paul Eiding, Will Friedle, Wallace Langham, and Richard McGonagle.

Gorvan (voiced by John DiMaggio in Alien Force, Rob Paulsen in Omniverse) is a Tetramand criminal. Gorvan is initially a traitorous Plumber who debuts in a tie-in video game to Alien Force, before reappearing as an ally of Psyphon in Omniverse.

Argit (voiced by Alexander Polinsky) is a rat-like alien con man and friend of Kevin. Having befriended Kevin, Argit became an associate after their memories of the Rooters were erased. He possesses venomous quills that can paralyze anyone exposed to them. In Omniverse, Argit ends up becoming a respectable member of Undertown society after helping fend off the Incurseans' invasion.

Michael Morningstar (voiced by Wil Wheaton in the classic continuity, Drake Bell in the reboot episode "Bright Lights, Black Hearts", Yuri Lowenthal in the reboot episode "The Charm Offensive"), also known as Darkstar, is the son of a Plumber, initially depicted as a well-mannered individual from an upper-class family and a menagerie of Plumber technology. However, he shows a very uncaring attitude to others around him. Furthermore, he is a vampire-like being, his abilities allow him to absorb energy of another living being to gain the ability to project energy bolts, fly, superhuman strength and stamina, and healthier-looking skin. His victims, on the hand, become zombie-like and loyal to him. Morningstar's powers are a vicious cycle: gaining more power from the mass of life force energy he drains yet it increases his hunger for more.

The Incurseans are toad-like aliens who were forced to become spacefarers after their planet was destroyed during a civil war.

Milleous (voiced by Kevin Michael Richardson in the classic continuity, Roger Craig Smith in the reboot) is Attea's father and the former leader of the Incurseans. He is rather indifferent, seemingly having no concern for the well being of others with his family included as he had his wife imprisoned.In the Omniverse episode "The Frogs of War", Milleous leads the Incurseans' invasion of Earth and even gets Ben to surrender after unleashing an army of mutated To'kustars. Due to Attea's scheme, Milleous is defeated and put in Plumber custody.

Attea (voiced by Tara Strong) is an Incursean princess and the daughter of Emperor Milleous, who she later seizes power from.

Raff (voiced by James Arnold Taylor in Alien Force, Eric Bauza in Omniverse) is a Sylonnoid commander who serves the Incurseans.

SevenSeven (voiced by Dee Bradley Baker) is a Sotoraggian bounty hunter and SixSix's brother. Unlike Sixsix, who uses weapons hidden in compartments of his armor, SevenSeven's hands can transform into various weapons and tools.

Albedo (voiced by Eric Bauza in Galvan form, Yuri Lowenthal in human form) is a Galvan who was originally Azmuth's assistant. He built his own version of the Omnitrix, which transformed him into a clone of Ben. Initially resembling an exact copy of Ben, Albedo is later damaged by feedback from the real Omnitrix, giving him white hair and red eyes. In the Omniverse episodes "A Fistful of Brains" and "For a Few Brains More", Albedo plots to steal Azmuth's intelligence to augment his own, but is thwarted and trapped in an eleven-year-old form by Azmuth.

The Queen (voiced by Wendy Cutler) is the queen of the Nanochips.

Psyphon (voiced by Dee Bradley Baker) is an alien and former servant of Vilgax who later becomes an independent criminal.

The R.E.D.s (Robotic Extermination Devices) are red robots who work for Psyphon.

Ssserpent (voiced by Dee Bradley Baker) is a snake-like alien criminal.

Octagon and Rhomboid Vreedle (respectively voiced by John DiMaggio and Rob Paulsen) are Vreedle mercenaries who are the sons of the infamous criminal Ma Vreedle. Octagon is the older brother, slightly more intelligent with more mature, serious and down-to-earth personality, yet can still be easily tricked such as when Gwen distracted him and his brother with bubble wrap. Rhomboid is the least intelligent of the siblings who is the brawn of the two with a habit of always blowing things up with a large weapon. As he is the younger brother, despite being larger in size, he usually follows Octagon's orders with occasional foul-ups on his end. The Vreedles have a form of semi-immortality, meaning even if they are killed, their memories are transferred into another "set" of clones who will take their place.

Sunder (voiced by Powers Boothe in Alien Force and Ultimate Alien, David Kaye in Omniverse) is an alien bounty hunter who wields an axe. His axe can send whatever it hits to another dimension.

Jarret (voiced by Alexander Polinsky) is the leader of the Pantophage.

Will Harangue (voiced by John DiMaggio) is a news anchor (a parody of J. K. Simmons' portrayal of J. Jonah Jameson^[7]) who believes Ben to be a menace. In Omniverse, Harangue broadcasts propaganda for the Incurseans during their invasion of Earth. This led to him suffering lowered ratings with less sponsors, forcing him to fund the Forever Knights while being ignorant of their actual intentions. Ben as Juryrigg rewires the Forever Knights' machine to turn Harangue into a mutant squid-like alien.

Aggregor (voiced by John DiMaggio) is an artificial Osmosian who became an intergalactic criminal and serves as the main antagonist in the first season of Ultimate Alien. He was originally created by Servantis as an enhanced clone from Kevin's DNA to destroy Ben after the Amalgams failed. After Ben gave up the Omnitrix, Servantis stopped targeting him and set Aggregor free after erasing his memories. Like Kevin, Aggregor can absorb any type of matter and energy and use them by force of will, with his own natural abilities, or with his staff. While he uses robots, Aggregor prefers to carry out his plans himself rather than let his henchmen do the work. Aggregor is a highly skilled hand-to-hand combatant and caries a powerful spear which he can use as either staff or spear to stab targets or fire blasts of red energy that can disrupt other energy fields, stun targets, or disrupt machinery.

Carl Nesmith (voiced by Christopher McDonald) is a famous superhero known as Captain Nemesis, a great American icon, and Ben's idol. He stated that he had been a hero before Ben was even born, and his long services made him rich and famous, having his own weapon-making company and comic book series. In reality, Nesmith is a greedy gloryhound and a fraud who stages the crimes he stops for profit.

Computron (voiced by Dee Bradley Baker) is a robotic villain who was imprisoned in Dimension 12. In the Omniverse episode "Arrested Development," it was revealed that Billy Billions encountered Computron and his robot minions after he was accidentally sent into Dimension 12. Billions managed to create a watch-like device that would enable him to control the robots and have them build a portal that would take him back to Earth while using them to kill Ben. Once Billions' device overloads, the robots revert to their original programing, with Billions aiding Ben in returning the robots to Dimension 12.

Xarion (voiced by Peter Stormare) is the aging king of the kingdom of Zarkovia. Xarion is later imprisoned along with Ben and his team until he is released by Gwen. Xarion then makes off with Ben and takes it along with Dr. Viktor to his son Gyula's laboratory. Xarion transfers his mind into Viktor's body, but is stopped by Ben and imprisoned in hardened metal. In the Omniverse episode "Rad Monster Party", it is revealed that Xarion's consciousness was destroyed by Zs'Skayr, allowing Viktor to regain control of his body..

Addwaitya (voiced by John DiMaggio in Ultimate Alien, Steve Blum in Omniverse) is a mutant Geochelone Aerios who is known as the master and Lord of Ledergdomian in addition to being the murderer of Charmcaster's father, Spellbinder.

Pa Vreedle (voiced by Jeff Bennett in Ultimate Alien, Steve Blum in Omniverse) is Ma Vreedle's ex-husband and the father of the Vreedle Brothers.

Trumbipulor (voiced by Dee Bradley Baker in Ultimate Alien, Eric Bauza in Omniverse) is an elephant-like alien criminal. He is able to grow to a gigantic size by eating peanuts.

Dagon (voiced by John DiMaggio) is an interdimensional squid-like entity. He was claimed to visit Earth during the Middle Ages, and gave humans advanced technology. He is believed to have sworn to come back to Earth to bring the "Golden Age", claiming he will bring more alien technology and make Earth a utopia. In reality, Dagon tried to invade Earth in a dragon-like form with the help of his Lucubra army until Sir George defeated him by cutting out his heart. In the present, Dagon manages to escape his dimension by destroying the seal that kept him from entering Earth. Dagon is apparently killed when Vilgax converts him into energy and absorbs him.

The Lucubra (voiced by Dee Bradley Baker) are animalistic creatures under Dagon who have the ability to feed on thoughts. The victim then becomes an obedient servant to Dagon, evident by their eyes turning turquoise. However, the mind control is negated if a victim's cranium is protected by metal.

The Flame Keeper's Circle is a cult that worships Dagon. They consist of Conduit Edwards (voiced by John DiMaggio) and the Esoterica, foot soldiers who can teleport between dimensions.

Ma Vreedle (voiced by Diane Delano) is a notorious criminal and the leader of the Vreedles. She is considered one of the most dangerous criminals in the universe. Debuting in "Mother of All Vreedles", Ma steals numerous pieces of cloning machinery to create countless clones of his new son Pretty Boy using Earth's oceanic supply of salt water. However, she ends up being turned in by her sons. Kevin fears her, describing her in contrast to her sons as "less stupid, more mean".

Inspector 13 (voiced by Dee Bradley Baker) is an illegal weapons dealer and a former Techadon Weaponmaster. The Weapons Masters of Techadon create, supply and sell weapons to anyone who can afford them from their homeworld of Techadon. They are cold and calculating with no concern only the intent of those who buy their products, only caring to make better weapons.

Malware (voiced by Corey Burton) is a mutant Galvanic Mechamorph who was born with an emaciated, yellow appearance and the ability to absorb technology rather than enhance it. Frustrated by Azmuth's refusal to heal him, Malware steals the cure he created and assumes a monstrous red form. Malware later forms an alliance with Khyber and Dr. Psychobos to combat Ben, creating the Nemetrix from stolen Omnitrix data.

Khyber (voiced by David Kaye) is a Zaroffian hunter who was hired by Malware and Dr. Psychobos to go after Ben, told that he was a worthy prize to hunt. To aid in his hunt, Khyber is given an Omnitrix-like item called the Nemetrix which he uses to turn his hunting dog Zed into a variety of predatory species. Khyber later abandons Zed, who is adopted by Kevin. He obtains a Panuncian, a wolf-like predator with the ability to duplicate itself, as Zed's replacement, equipping it with the Nemetrix.

Dr. Psychobos (voiced by Eric Bauza) is a cybernetically enhanced Cerebocrustacean who helped Khyber create the Nemetrix. He intends to prove the intellectual superiority of himself and the Cerebrocrustaceans over Azmuth and the Galvans. He later enacts his plan to kill Azmuth during "Showdown" with Khyber before being abandoned by the hunter and then placed under arrest.

A group of criminal aliens that reside in Undertown. They are mainly hired by Psyphon for different plans, but also act independently to commit other criminal acts.

Bubble Helmet (voiced by John DiMaggio) is a caterpillar-like alien who wields powered armor that enables him to breathe.

Fistina (voiced by Morgan Lofting) is a cybernetically enhanced Acrosian who uses a containment suit as battle armor and can shoot her fists like rockets. Later in the series, she reforms and considers joining the Plumbers.

Liam (voiced by Paul Eiding) is a chicken-like alien of the same species as Kickin' Hawk.

Thunderpig (voiced by Eric Bauza) is a pig-like alien who wields an electrified flail. Thunderpig exhibits enhanced strength which he uses to lift and throw a glowing flail that he uses to attack others with. His design and name are a parody of the ThunderCats franchise.

Tummyhead (voiced by Rob Paulsen) is a two-headed alien who works for Psyphon.

Sweet-Eels Sparklefunk (voiced by Kevin Michael Richardson) is a tentacled alien who works for Psyphon.

Bouncer (voiced by Bumper Robinson) is an unnamed alien who works for Psyphon.

Bug-Lite (voiced by Bumper Robinson) is an insect-like alien who works for Psyphon.

Fistrick (voiced by Eric Bauza) is a super-strong small-time crime lord and arms dealer. He has a lot of connections, often responding that he "knows/knew a guy" as the answer to a question.

Solid Plugg (voiced by Eric Bauza) is a freelance criminal and resident of Undertown.

Looma Red Wind (voiced by Kimberly Brooks) is a Tetramand princess who Ben becomes betrothed to after defeating her in solo combat. In the episode "Rules of Engagement", Looma travels to Earth and kidnaps Esther, Julie and Rook. She is defeated by Ben as Ball Weevil and agrees to call off their engagement.

Billy Billions (voiced by Aziz Ansari in Omniverse, Gunnar Sizemore in the reboot) is a billionaire and childhood rival of Ben. In an attempt to get rid of Ben, Billions was trapped Dimension 12 and spent five years there without aging, which left him incapable of aging. In the episode "Arrested Development", Billions returns to Earth and uses his army of Dimension 12 robots to enact revenge on Ben by turning him and Rook into eleven-year-olds. When Billions loses his means to control the robots, he briefly works with Ben and Rook to stop the robots before being arrested by the Plumbers.

Mazuma (voiced by Tara Strong) is an android and Billy Billions' servant.

Nyancy Chan (voiced by Gwendoline Yeo) is a mutant criminal who can control felines.

EightEight (voiced by Dee Bradley Baker) is a Sotoraggian bounty hunter and the older sister of SevenSeven and SixSix.

The Way Bads (voiced by Eric Bauza) are mutant To'kustars created by Dr. Psychobos. They are introduced in "The Frogs of War", where they assist the Incurseans in their invasion of Earth. The Way Bads are later transported to the Null Void by Rook after breaking Psychobos's hold over them.

Crüjo (voiced by Bumper Robinson) is a bear-like Loboan who works for Zs'Skayr.

Kuphulu (voiced by Jeffrey Combs) is a Thep Khufan who works for Zs'Skayr.

Lord Transyl (voiced by David Kaye) is the former leader of the Vladats, who were killed in a war with the Transylians. In the present day, Zs'Skayr resurrects Transyl using the Alpha Rune and convinces him to join forces to take over Anur Transyl's population while resurrecting the rest of the Vladats to extend their control to the rest of the universe. When Zs'Skayr orders Lord Transyl to get Ben Tennyson under his control, Viktor turns against Lord Transyl and the plan fails, followed by Ben defeating Zs'Skayr and Lord Transyl. Viktor imprisons Transyl in a casket stationed to face a star to keep him in a weakened state.

The Rooters are a high-ranking black ops unit of the Plumbers who transformed themselves into alien hybrids using Kevin's abilities. The group is led by the half-Cerebrocrustacean Proctor Servantis (voiced by Charlie Adler) and consists of the Aerophibian hybrid Swift (voiced by Tara Strong), the half-Prypiatosian-B Leander, and Phil Billings. The Rooters were originally dedicated to killing Ben and transformed the Plumber Kids into alien hybrids to aid their cause. After Ben gave up the Omnitrix, the Rooters no longer saw him as a threat and gave up their mission. Servantis purged Kevin, Argit, and the Plumber Kids of their memories from their time in the Rooters and let them go. In the present, Servantis takes control of the Plumber Kids and forces them to attack Ben. Feigning loyalty to the Rooters' cause, Kevin frees the Plumber Kids from Servantis before the Rooters are disbanded by the High Protectorate. They are then transported in the Null Void and left at the mercy of the Way Bads.

Kundo (voiced by Jeff Bennett) is a Revonnahgander traditionalist who believes his people are being poisoned by outside influence. While he was originally tolerable to allow Rook to join the Plumbers, Kundo was against Rook Shar's enlistment and pursued her to bring her back to Revonnah by any means. Kundo is seemingly killed after being attacked with the acidic Blastonium. He is later revealed to have survived, but was left with severe burns and given cybernetic prosthetics.

Maltruant (voiced by Mark Hamill) is a Chronosapien who seeks to control the time-space continuum and is the main antagonist of the final arc of Omniverse. He was previously involved in a time war before his body was broken in several pieces and placed in various points in time and space. Maltruant first appears in the episode "Fight in the Museum" when he hires Subdora and Exo-Skull steal the Key to Time, one of his body parts, for him. After being completely repaired, Psychobos proceeds to start a new time war with Eon providing him with two Time Beast eggs. Maltruant then travels to Ben's future timeline to steal the Anihilaarg and modify it with a Dwarf Star before using the Time Beasts to reach the beginning of the universe and recreate it in his image. Maltruant is destroyed by Ben and trapped in a time loop where he would eventually be rebuilt and repeat his actions up to being destroyed.

Subdora (voiced by Tara Platt) is a Merlinisapien thief who works for Maltruant and is partnered with Exo-Skull.

• Ben 10 Characters official US site