Halo is a popular series of first-person shooter video games developed by Bungie Studios and published by Microsoft. Halo quickly became known as the first "killer app" for Microsoft's Xbox console when it was released in 2001, achieving both critical acclaim and financial success. The game was later published on the PC and finally released for the Mac (for which it was originally developed prior to Microsoft's buying developer Bungie). A second game, Halo 2 was released in 2004, and the third game, Halo 3, was announced as available in 2007 for the Xbox 360, during Microsoft's press event at the E3 Expo in Los Angeles on May 9, 2006. The Halo games have become well known for their impressive graphics, polished gameplay, realistic physics, and engaging storyline; these are characteristics they share with previous Bungie works, including the Marathon series on the Mac. Further enriching the Halo universe are several novels, which provide insight into the background story, and a movie currently in pre-production.

Template:Spoiler Halo was the most popular application for the Xbox console up until the release of its more ambitious sequel, Halo 2. The series follows the events of the full-scale holy war between future humanity and a collective of alien races known as The Covenant. The player takes on the role of the Master Chief, a human supersoldier (aka Spartan II) equipped with a technologically advanced battle armor. The game play takes place in fights against the Covenant , on and in the mysterious Halo until the player reaches its most deadly secrets.

Halo: Combat Evolved is a first person shooter that takes place on a mysterious ring world named Halo. Set in the year 2552 AD, it focuses around a stage in a war between Humans and an alliance of technologically superior alien races known as the Covenant, united by their fanatical religious beliefs. The protagonist is a highly trained and bio-engineered cyborg, and a subject of the SPARTAN-II project, a classified assignment to create a handfull of super-soldiers, originally intended to furtively board a Covenant warship with the intent of finding the location of the Covenant homeworld. However, the planet Reach, where all but one of the super-soldiers are on a mission, is invaded by the Covenant, and all life on the surface is utterly annihilated. Only one vessel escapes, the Pillar of Autumn, carrying the last SPARTAN-II, who is known only as the "Master Chief."

Just before the Pillar of Autumn is attacked and easily taken over by the Covenant Warships in pursuit, Captain Keyes, the highest ranking officer on board, lands the ship on the mysterious ring-shaped world known as Halo, while many marines and the recently defrosted Master Chief (who was in cryogenic stasis) escape to Halo in lifepods, despite the many attempts of the Covenant forces to stop the humans from landing on the supposedly sacred ring.

In the ten levels of the game, the Master Chief must, with the help of the AI construct Cortana, and occasionally with the help of marines, fight off the Covenant forces and the two other factions (the Flood and the sentinels of 343 Guilty Spark) which are unveiled during the game, and the Master Chief must discover the true purpose of Halo.

Halo Custom Edition is an expansion of the PC version of Halo: Combat Evolved. It is used to load user-created content (mods) that were created using the Halo editing kit.

Halo 2 was released for the Xbox on November 9, 2004 in two different editions; the standard Halo 2 edition came in the traditional Xbox packaging, featuring a single disc with the single player campaign and multiplayer components. Also a Halo 2 Collector's Edition was released in a specially designed metal case, including an additional bonus DVD, extra booklet and slightly different user manual that accompanied the game. The sales of both units combined generated a $125 million entertainment record on its premiere day and over 7 million copies of the game have been sold world wide. It was recently announced that a PC port for the Windows Vista operating system is currently in development by an internal team composed from both Microsoft Game Studios and Bungie Studios.

The sequel features new game mechanics such as dual wielding, new vehicles and weapons, better A.I., the ability to hijack vehicles, and Internet-based multiplayer via Xbox Live. Some easily seen changes between Halo 2 and its predecessor are in the weapons arsenal, which features a new battle rifle, a scopeless pistol, a submachine gun and the Covenant Carbine; also a new Covenant vehicle known as the Spectre has been included and previously seen vehicles such as the Warthog, Ghost, Banshee and Wraith have new features or weaponry. Halo 2 also introduces a new playable character in the form of a Covenant Elite called The Arbiter. The game has a reworked, more advanced graphics engine than the original, that utilizes normal mapping and bloom effects, helping to make it one of the best looking games on the Xbox. It also has Bungie.net integration and rankings and tracking of every online match, pushing the envelope of online console gaming further. Halo 2 supports the same LAN and split-screen multiplayer found in Halo: Combat Evolved.

Although Halo 2 is much more ambitious than its predecessor, both through the scope of its campaign and the inclusion of new features, there is heated debate over whether the game is inferior compared to its predecessor, mostly from the viewpoint of competitive multiplayer gamers.

Again, the game places the player in the first-person perspective of the Master Chief, as well as the perspective of the Covenant Elite known as the Arbiter, in some levels. Again the Master Chief is consistently aided by the advice of Cortana throughout the game.

The first three levels are from the perspective of Master Chief, where he has returned to Earth, only to find that soon after a small Covenant force inevitably finds Earth and attacks it. After the Master Chief, marines and planetary defenses destroy most of the force, the last remaining Covenant ship escapes by performing a devastating sub-space entry inside a major city of Earth, and they are followed by a ship on which the Master Chief is present, and which is under the command of Captain Miranda Keyes, the daughter of the dead Captain Keyes from the original Halo game.

The rest of the levels are set on another Ringworld, and again sets either the Master Chief or the Arbiter against the Flood, the Covenant (even the Arbiter must fight Covenant forces, mainly Brutes, as part of the civil war which has broken out in the Covenant empire), and more Sentinel flying mechanisms. More disturbing secrets of the network of Ringworlds are uncovered during the game, and it ends on a cliffhanger, with the Master Chief onboard a ship, which the Prophet of Truth is also aboard, heading to earth "to finish the fight", and to go to the Ark as seen in the Halo 3 Trailer. The Arbiter, in an unlikely alliance with Miranda Keyes and other marines and covenant, are interrogating 343 Guilty Spark (the monitor of the Halo seen in this game is held by Gravemind), after destroying the Brute leader Tartarus, and attempting to stop the activation of the Ringworlds.

Halo 3 is third and final installment in the Halo series. At Microsoft's E3 2006 Press Conference they announced the trailer for Halo 3. As shown in the trailer, Master Chief is walking on a desert area with wreckage that resembles parts of the space elevator of New Mombasa. As Master Chief is walking, Cortana speaks the following lines (note that all lines except the last are 8 syllables):

I have defied Gods and Demons

I am your shield, I am your Sword

I know you; your past; your future

This is the way the world ends

It can be assumed from these words that Cortana is in a difficult position. She has been left in the Covenant capital of High Charity and she is now in the clutches of the Flood creature Gravemind. Master Chief halts on a cliff overlooking a Forerunner Artifact that the Covenant seem to have found and are opening, which is possibly the Ark (referenced by 343 Guilty Spark). It has been hinted that the Ark is possibly on Earth, under what used to be New Mombasa (which was vaporized when Regrets flagship made a slipspace jump inside the city), or Earth itself.

Some fans believe Halo and Halo 2 were influenced by a number of other games and pop culture references, partially based on the game series own references to some of these pop culture icons. These include StarCraft, the Alien and Predator movies, the Marathon series (also created by Bungie, makers of Halo) and Larry Niven's Known Space universe. No comment has been made about these possible influences by the developer and these ideas are only speculation.

A number of weapons and plot devices seem to borrow from ideas seen in the Marathon series of first-person shooters made by Bungie in the early to mid-1990s (see List of weapons in the Halo universe).

These include the concept of MJOLNIR "cyborgs", the supersoldier main character, the weapons, artificial intelligences, Marathon class cruisers in the UNSC, and even some of the alien creatures. Upon close inspection, crew members of the Pillar of the Autumn have the Marathon symbol on their uniforms, and the symbol is even embedded in the Halo logo itself. The Elites from Halo are somewhat similar (in their appearance, not their role) to Marathon's Pfhor. Hunters appear in both games filling the same roles. The Hunters from Halo, though much larger, also clearly share design elements with the Hunters from Marathon. A type of alien that was modeled for Halo 2 but later cut is nearly identical to the Drinniol from Marathon. Also, both games use uniform color to differentiate between different ranks of aliens (and crew members), with higher ranks being stronger and harder to kill. There are two multiplayer gaming options, a version of King of the Hill, a game called Oddball (called "Kill the Man with the Ball" in Marathon), "Every man for Themselves" which is similar to slayer, and Tag which are present in Marathon's multiplayer mode.

These large similarities led to early speculation that Halo took place in the same universe as Marathon, only with different time frames; however, this was later proved highly unlikely. According to both the Halo video games and books, the events in Halo coincide with the events in Marathon. However, due to technology differences (the lack of transporter technology in Halo, for one), this is impossible. On Bungie's own Marathon page, there is a Q&A which states, "Is Marathon the prequel to Halo? [...] No, Marathon is a separate story, with wholly different characters, story and gameplay." [1].

Also, like Marathon, Halo also has plenty to do with the number 7. The characters 343 Guilty Spark (7 cubed) and 2401 Pentinent Tangent (7^4 and 2+4+0+1=7). There are 7 Halos. There are also some other subtle 7 references, but some seem more like coincidence, like Cortana having seven leters. July 7th or 7/7 is Bungie Day.

Some film parallels in the games have been pointed out by various people. For instance, the active camouflage power-up is very similar to the type of camouflage used by the alien Yautja in the Predator film series. There are notices near the Pillar of Autumn's bridge looking for a cat named Jonesy (the name of Sigourney Weaver's cat in the Alien film series). Elites' mouth parts are similar to the Predators' with bodies very similar to the Xenomorphs. The Flood Spores share a similar purpose with the Facehuggers in the Alien film series. Private Frost says "I've got a bad feeling about this, man" and is answered with "Man, you always got a bad feeling!", a quote which is used in the cut-sequence right before Master Chief has his first encounter with the Flood. Also, there are numerous similarities between the marines of Halo and those of Aliens in the way that they dress and the weapons they carry. The colonial marines' dropship resembles a Pelican and the Pelican pilot Foe Hammer is based on the dropship pilot from Aliens. Finally, Halo's Sergeant Johnson is very strongly based on Aliens' Sergeant Apone - both are very enthusiastic, black, cigar-smoking squad leaders. Both characters even use the line "They're not paying us by the hour, marines!"

In the film "Demolition Man", Sylvester Stallone's character's name is John Spartan, Master Chief's (aka "Spartan 117") first name is John.

In Robert A Heinlein's novel Starship Troopers, supersoldiers wear powered armor that acts in a similar manner to the Master Chief's suit. The main cannon of the Covenant tank fires a plasma round similar to those fired by certain bugs in the movie adaptation of the novel. There are also strong similarities between the spaceships in Halo and those in the movie.

Ringworld is a megastructure 93 million miles in radius that resembles the Halo installations, albeit on an enormously larger scale. This idea has been copied numerous times in science fiction, although normally on a larger scale than in Halo. In both Halo and Known Space, humans develop space travel on their own and later encounter a hostile and technologically superior alien civilization. In one of Larry Niven's early Known Space novels, World of Ptavvs, it details an alien race, known as the Thrintun, and how they ruled a massive empire 2 billion years before humanity, through advanced mind control. At one point, the Thrintun's most advanced slave race eventually instigated a massive rebellion, using much of their own technology, which was developed for their masters, against them. The Thrintun, fearing extinction and intense paranoia, used an amplification device that targeted the minds of all sentient lifeforms and simply told them to "die". The wave from this device spread across the entire galaxy, killing all sentient life, including the Thrintun themselves. In Halo, the Forerunners used the Halos to extinguish all sentient life in the galaxy, in order to prevent The Flood from escaping the Halo installations.

Halo took names from world history and mythology to aptly name objects and important characters in the Halo universe. Some of these names include:

• Cortana, derived from a sword used by Edward the Confessor.
• Beowulf, a hero in the Anglo-Saxon poem "Beowulf".
• Tartarus, a deity and a place in the Greek mythological underworld.
• MJOLNIR, Thor's Hammer.
• SPARTAN, the Ancient Greek polis of renowned martial prowess, Sparta.
• Foehammer, the name of the sword wielded by Gandalf in The Lord of the Rings.

Alternatively, it is possible (or even likely) that Halo was inspired by the Orbitals featuring in The Culture novels by Iain M. Banks, as they are ring-shaped megastructures that orbit stars or gas giants, rather than rotate around them. These smaller structures have the advantage of not needing additional machinery to generate a day/night cycle. Furthering this theory is the fact that the Covenant resemble in no small measure the Idiran race, religious zealots bent on eradicating The Culture, which they regard as heretical; or that the Forerunner robot 343 Guilty Spark resembles a Culture drone. The titles of the ships, and the names of the levels are extremely similar to the naming method Banks uses in his novels; whimsical names in Marathon and Halo are common, "Guilty Spark", "Never Burn Money" etc. are arguably similar to the Culture ship's names, "Nervous Energy", "Sleeper Service", "Grey Area"

Halo seems to be inspired by a number of other science fiction books, such as Orson Scott Card's Enders Game and Starhammer by Christopher Rowley. Starhammer details the story of a genetically altered man named Jon 6725416 who escapes slavery by a race of technologically advanced overlords threatening to destroy humanity, and finds an ancient weapon that was created by an ancient race to destroy a parasitic alien life form called the Vang that may have been a partial basis for the Flood. Also of note is that Foehammer, the dropship pilot in the first game, is canonically named "Carol Rawley," adding a further connection. 343 Guilty Spark is also very similar to Durandal, an AI from Bungie's earlier Marathon Series, as the two seem to share a similar manner of speech. Both Durandal and 343 Guilty Spark also "control" the player during gameplay, directing the player where to go and opening certain doors to aid progression. In the book Starship Troopers, the Mobile Infantry are equipped with powered armor and are launched down to the surface of a planet in pods, not unlike the Spartans and ODSTs of Halo. The species in the Halo series also share similarities with Blizzard's StarCraft series, especially the "Three Races" concept: "Terran, Protoss, Zerg" as opposed to "Human, Covenant, Flood". The parallels between the Protoss and Covenant are more marked; both are portrayed as very technologically advanced, deeply religious races. The Flood and Zerg are also both parasitic species that assimilate other races. Both the UNSC and the Terrans utilize technology that is seemingly not very "modern" when compared to other humans in science fiction works, despite the hundreds of years the humans in both games have had to advance. Another possible sci-fi influence is from David Weber's book Path of The Fury. In it, Elysium, AI's, and even the name of a character: Colonel Watts. Elysium, in Halo, is the city which John-117 (SPARTAN-117) is born and raised. AIs are used in the ships of the Imperial Fleet of David Weber's book, and Colonel Watts, a governor of rebels in Halo: The Fall of Reach book.

The following references are possible Bible references, and they may be able to help us get a better understanding of the game's storyline.

"The Covenant"

In the Bible, there were three Covenants (agreements or contracts) between God and humanity, made by Noah, Abraham and Moses.

"Prophets"

Prophets helped lead the people of Israel, and kept them from losing sight of the promise that the Covenant represented.

"The Ark"

The word "Ark" has three contexts in the Bible. First, it refers to the boat constructed by Noah to save his family and two of every living creature from the Great Flood. Second, it refers to the so-called "Ark of the Covenant", the vessel which held the stone pieces of the original Ten Commandments. Thirdly, it refers to the "ark of bulrushes" in which and infant Moses was placed and then set into the Nile River by Moses' mother to prevent his death.

"The Flood"

The Great Flood is sent by God to destroy humanity, with the exception of Noah and his family, in Genesis.