List of inconsistencies in the Halo series

This list is compiled to show the various discrepancies spotted in the Halo universe. It is difficult to decide which resource is "superior" to another, so usually, the inconsistency is mentioned in the articles that it involves.

If you think you can explain an inconsistency, do so here, on the article's talk page.

There are two types of inconsistencies: Conflicts and Discrepancies. Conflicts happen when two sources say two different things about the same object. Discrepancies occur when a seemingly impossible event happens without any explanation.

Halo: The Fall of Reach

 * On page 46, Kelly handed out parts of a map to the seventy-five SPARTAN-II trainees, but on page 48, when John checked to make sure all the children arrived at the lake, he counted only sixty-seven, which seemed to be all of them.
 * The London: included as a mistaken reference to the UNSC Pioneer in some early editions.
 * A faster-than-light drive is first referred to as a "Shaw-Fujikawa" engine, and later as "Fujikawa-Shaw".
 * A UNSC frigate was referred to as the UNSC Alliance, and then shortly thereafter as the UNSC Allegiance.
 * The ship UNSC Leviathan is referred to as a cruiser and then later as a carrier.
 * On page 19, Michael Stanforth was said to be a Vice Admiral, and on page 95, it said he was a Rear Admiral. It is very rare for the brass to be demoted, as they have achieved a lot to earn their rank.
 * James' left/right arm was burnt off by a Fuel Rod Cannon. However, he could easily have been given a flash-cloned arm afterward.
 * In 2552, Doctor Halsey is only speculating the existence of the Elite race. Elites were, however, encountered by humans before in at least the Battle of the Rubble, the First Battle of Arcadia where the Spartan Red Team and Group Omega fought. They were also recognized by Kurt in a mission recording, and most importantly, the UNSC captured one alive during the Battle of the Great Bear.
 * The Pillar of Autumn was missing its port-side emergency thrusters, but later used them twice.
 * While riding to Reach Station Gamma, Kelly-087 tells the Chief that the Spartans are "All secure." Kelly isn't even in the Pelican at the time. Either the author meant to say "Linda", or Kelly spoke on com, although there would be no reason for the latter.
 * During Master Chief's mission to Reach Station Gamma, a Jackal's blood is said to be blue while it is clearly purple. The same mistake is made with the Elites as well, saying that their blood is green, while it is also purple.
 * On the cover, it shows 4 Spartans in Mark V MJOLNIR Armor on Sigma Octanus IV, but the Mark V was issued after The Battle of Sigma Octanus IV.
 * It describes Lt. Hikowa as male, but then later refers to the lieutenant as female.
 * On two occasions, it is stated that the Spartans had standing orders to retrieve Covenant technology.

Halo: Combat Evolved

 * Main view screen of the Pillar of Autumn labels the as-of yet unidentified ring as "Halo". The ring is not officially named until the level Truth and Reconciliation
 * The view screen could have been referring to it by its shape.


 * Cortana says she cannot begin to calculate the pulse range of Halo just after 343 Guilty Spark finishes telling her it has a radius of 25,000 light years.
 * This can be accounted for by Cortana's inherent distrust of Guilty Spark's motives (she had just recently sworn at him), though. Additionally, since Cortana is an AI with an insatiable urge to know everything she can, she may have tried to calculate the range herself regardless of whatever 343 Guilty Spark had simply told her.


 * Almost every Pelican dropship bears the marking E419 on its side, despite that each Pelican has a different ID number.
 * Bungie only designed two models. They used the two to represent any Pelican.


 * Pvt. Jenkins' Record View on the level 343 Guilty Spark shows the date as the 27th of May 2552 when The Maw clearly takes place on September 22.
 * Frankie has confirmed that the date calibration of his equipment was not performed, causing the apparent discrepancy.


 * The pilot of the Master Chief's lifeboat is referred to as "Lieutenant", but says "Aye aye, sir" to the Master Chief, even though Lieutenant is a higher rank than Master Chief. However, this could be due to the fact that nearly all UNSC personnel owe subordinate respect to the Spartans to some degree.
 * John-117 had mission command and thus commanded all survivors, since his orders came directly from Captain Keyes, the commander of the entire operation. His mission was to get Cortana off the ship, and therefore he had tactical superiority.


 * In The Maw, the main objective is to trigger a Wildcat destabilization of the Pillar of Autumn's fusion reactors. Later, Cortana tells Foehammer that the engine sustained more damage than she thought because of the Wildcat destabilization.
 * Note that this may be due to the fact that the engine decay rate was faster than Cortana originally anticipated, she theorized it must have taken damage on impact -- or she didn't want to admit that they were blowing up the ship and used it as an excuse.


 * Also in The Maw, the player has to travel over 3 kilometers to reach the Longsword, but the Pillar of Autumn is only 1.17 kilometers long.
 * This may be due to the route curving, detours, and other maneuvers increasing the distance. This is unlikely, though, as the NAV marker does not account for such maneuvers -- it adds distance when moving away from the objective.
 * Also, some speculate that Master Chief would've turned 180 degrees, although it is proved that he didn't.
 * The Longsword's launch bay in The Maw is also at the end of the (rather straight)Warthog run. The front or rear of a ship is an unlikely place to store a launch bay, which implies that Master Chief traveled from side to side. This contradicts more to the Pillar of Autumn's length and side.
 * In Halo: The Fall of Reach, Hikowa and Dowski are female officers of the Pillar of Autumn. However, on the level Pillar of Autumn, the bridge (HQ of a ship) has no female members.
 * Female Naval crew skins (apart from the unnamed Lifeboat pilot) were not designed for the game.


 * William Lovell's eyes are green, but the Autumn's crew has no green-eyed members.
 * Game designers do not generally colour the Iris, instead only showing the Pupil.


 * Unggoy combatants can be heard shouting "Bad Cyborg!" at John-117. The Master Chief, however, is not a cyborg. The second chapter of The Pillar of Autumn exhibits the same inconsistency: it is called "AI Constructs and Cyborgs first."
 * This could be a reference to the main character of the Marathon series, or it could be because the Chief is able to carry an AI. Though he could be considered a Cyborg in the sense that MJOLNIR armour operates like "an extension" of their bodies.


 * During the level "Assault on the Control Room", S.Sgt. Johnson can be seen with the Chief at the time he was really with Captain Keyes searching for the Covenant's "weapon cache". Also, the Captain has been out of reach since The Silent Cartographer
 * This is a result of Bungie reusing Johnson's model instead of creating another Sergeant model.
 * In 343 Guilty Spark when John-117 arrives at the room in which he finds Pvt. Jenkins' mission recording, he opens the door and catches a body as it falls out, surely this body should have been infected by the Flood?

Halo: The Flood

 * On page 39, the Pelicans had to wait until they entered Halo's atmosphere. Pelicans are known to be able to operate in space, although this could simply refer to the pilots being delayed until they were in the atmosphere.
 * On the same page, there is a typo: "70mm chin gun". This should be "chain gun". However, its presence is inconsistent with other descriptions of similar UNSC ships.
 * Also, it could be that the gun was mounted on the chin.
 * During the Two Betrayals chapter, the Master Chief "went with the rifle and shotgun", and only a page later manages to come up "with his sidearm in his hand", though this could be a result of the book ignoring the two-weapon limit present in the Halo games.
 * During a skirmish with a force of 100 Ghosts, it states the snipers and rocket-launcher-armed Marines couldn't be hit by plasma fire, as the weapons were fixed and the marines were on a hill. Yet in the game, the Ghost's plasma cannons can increase or decrease their angle, and could quite easily have killed the marines, unless they were positioned on an extremely tall and steep hill.
 * On page 101, it stated that "the Spartan was carrying a full combat load of ammo, grenades, and other gear, plus two magazines for the M19 launchers", although the Master Chief was not carrying a Rocket Launcher at the time, and if he was, he was never seen using it.
 * It also states that, when John ran out of ammo on his MA5B Assault Rifle, he switches to his M6D Pistol. There are no pistols on that level at all.
 * On the Truth and Reconciliation chapter, it states that a Marine was killed and, "his rocket exploded harmlessly..." No Marines were seen weilding a rocket launcher on that level, nor are any seen with them throughout the entire game.
 * It states that 3 weapons would be unwieldy for the Chief, and not to mention "damn heavy", and further states he chose a shotgun and sniper rifle. Later, though, it states that an Elite sliced his sniper rifle (presumably with an Energy Sword), prompting the Chief to draw a pistol. It was never explained how he obtained the pistol; however, its small size may have exempted it from the Chief's personal two-weapon limit.
 * Sergeant Parker is referred to as a he, and then a she.
 * It was stated that Second Squad was completely consumed by the Flood, specifically saying that their numbers dwindled until two PFCs remained, before the last of the marines fell. A page later, however, Foehammer picks up the surviving Marines. This contradicts the other information, though it is possible that part of the second squad was separated, or that she didn't know second squad was entirely KIA.
 * First Lieutenant Melissa McKay's mission clock is prefixed by an extra 1. It should be noted, though, that the last time it shows her mission clock, the clock reads D+144:38:19, while on the Master Chief's last mission clock mention, it reads D+76:18:56. That's while he is en route to the Pillar of Autumn. It wouldn't take over 5 hours to detonate the ship, let alone 70 hours.
 * An encounter with 2 Jackals ends with one bullet ridden and the other plummeting off a cliff. However, following this a Marine steps forward and summarily shoots "each Jackal in the head".
 * Near the middle of the book, Spec Ops Elite Zuka 'Zamamee lays a trap for the Master Chief near the Silent Cartographer, coinciding with the game level of the same name. Afterward, he sends a Grunt spy to Alpha Base; the spy reports that the Chief has gone there sometime before the events of the level "343 Guilty Spark". This is impossible, as from the Silent Cartographer, the Chief goes straight to the area around the Control Room, and then straight to the swamps in the level. However, the book does say that Foehammer picked up the Chief to bring him back to Alpha Base, where he "scarfed a quick meal and a couple hours of sleep", so it is possible that Yayap saw him at that time.
 * Sergeant Stacker is not mentioned in the book. He is replaced during the raid on the Truth and Reconciliation by Sergeant Parker, and for the raid on the Silent Cartographer by Gunnery Sergeant Waller. The only place where he might make in appearance is when the Chief rescued a crashed Marine squad with a Sergeant, where Stacker is normally found in the game.
 * Several soldiers were referred to as both men and women, including Sergeant Parker and Second Lieutenant Oros.
 * At one point, the book states: "Consistent with his status as a veteran, the first alien to come around the corner wore red-trimmed armor, a methane rig, and a Marine's web pistol belt. The alien wore the captured gear Pancho Villa-style and dragged it across the deck. Two of his comrades brought up the rear." That is three Grunts in the Master Chief's sight. The next paragraph says, "Confident that there were more of the vaguely simian aliens on the way, the Master Chief paused long enough to let more of them appear, then opened fire. The recoil compensators in his armor dampened the effect, but he could still feel the handgun kick against his palm. All three of the Grunts went down from head shots." It is as if the extra Grunts that appeared simply disappeared. Only three Grunts were killed yet, which are the three original Grunts that first appeared, the leader and the two followers. But "...the Master Chief paused long enough to let more of them appear, then opened fire... All three of the Grunts went down from head shots." It is possible, though, that the Master Chief had simply expected more Grunts to appear; he may have simply waited in case more Grunts appeared, and then opened fire when he was sure there weren't any.

Halo 2

 * In the video "Another Day at the Beach", the Marines fighting are ODSTs. During gameplay, the Marines at the hotel are not ODSTs, they are just standard Marines. Also, the location of the crashed Pelican does not match its position in game.
 * This can be because the cutscene was cut from the original game.
 * In the level Delta Halo, you can find deceased ODSTs all around the level -- 7 to be exact. However, the In Amber Clad only dropped 11 HEVs. 3 ODSTs, the Master Chief, 3 more dead, and the seven dead ODSTs makes 14 Marines. This may just be a secret 7 reference, however, as 7=7 and 7x2=14. It is also possible that In Amber Clad launched more HEVs.

Halo: First Strike

 * The Longsword that landed in the Ascendant Justice is repeatedly referred to as a Pelican.
 * Vinh is referred to as Spartan-029, even though that was Joshua's tag. The mistake is probably a typo.
 * It is stated that Dr Halsey always referred to John by name, and never by rank or serial number. But in Halo: The Fall of Reach, she called him "Master Chief" repeatedly.

Halo: The Cole Protocol

 * Gray Team and the ODSTs used BR55 Battle Rifles, which were still prototype models at that time. However, as both Gray Team and the ODSTs were on special assignments from the Office of Naval Intelligence, it is possible that they were granted access to this non-standard weapon.

Halo 3

 * Every Longsword fighter bears the marking 7-89 on its side, despite that each Longsword has a different ID number. This is likely the result of reusing the same model.
 * In the ending cutscene of the level The Storm, all of the UNSC Frigates have the same serial code, and all are labeled "Forward Unto Dawn", when only one of them is the Forward Unto Dawn. This is also likely the result of reusing the same model.

Halo Wars

 * In the level Dome of Light, after requesting the first Rhino to be deployed, the radio operator on the Spirit of Fire will identify you as "Harvest Surface Command" even though the level takes place on Arcadia, however this could be that the Spirit of Fire was still assigned to Harvest.
 * The Spartans must be wearing Mark IV armor because the story takes place in 2531, 24 years before Reach would fall to the Covenant. However, the Spartans in the game possess recharging energy shields, a feature that would only be later added in the Mark V armor. This is probably only a gameplay mechanic and should not be taken as canon.
 * The Spirit of Fire is presumably equipped with a standard UNSC MAC. A destroyer-class vessel can fire 2 rounds with one charge, as it possesses 2 separate MACs. The Pillar of Autumn could shoot 3 rounds with one charge, as it possessed an advanced prototype. The Super MACs around Reach and Earth could fire one round every 5 seconds. But somehow, the MAC aboard the Spirit of Fire is able to deliver 4 rounds with a single charge, something that is unheard of in a shipborne MAC. However, as the rounds do very little damage to the area surrounding their targets, it may be assumed that the rounds or MAC itself are not standard, or that the rounds are fired with a lower-than-normal charge.
 * Only Honor Guards are permitted to wield energy staves. However, in the cutscene "Monsters", in which the Spartans are fighting with the Elites when Forge is trying to activate the reactor, blue-armored Elites are armed with energy staves. This may mean that these were Honor Guards composed of Elite Minors, or Elite Minors who were given energy staves to fight with.
 * In previous cutscenes with the Prophet of Regret, the Elites that are guarding him are clad in red armor, as Elite Majors are. Later, the Honor Guards are shown fighting the Spartans in blue armor. However, there is an explanation: the Arbiter ordered the red-armored Honor Guards to accompany the Prophet of Regret back to High Charity.
 * Despite being smaller in size than a Cruiser, in Halo Wars cutscenes, Destroyers are shown as being slightly shorter than a Phoenix-class Colony Ship, which is over two kilometers. However, this may be due to the fact the destroyer maybe a different class from those that are smaller than a cruiser, or that the cutscene's caption is in error.
 * In the cutscene where Professor Anders is captured, Red Team pulls up in a Warthog armed with a quad-barreled Gatling gun. Throughout the entire Halo series, the M41 LAAG has only 3 barrels. This is either a new variant of the M41 LAAG or simply an error on the part of the developers. This four-barrelled design is featured on all renders of the weapon that have been produced for Halo Wars, including those created for franchising purposes.
 * The Mk IV armor worn by Red Team and Team Omega does not resemble the armor in Halo: The Cole Protocol in any way save for general Mjonlnir characteristics. Though the the two versions may be different variants, they are so different in form that it is more likely that the Halo Wars version is entirely artistic license and that the one on the cover of the Cole Protocol, save for the left pauldron, is the correct Mk IV. Further evidence for this is that much of what is depicted in Halo Wars visually deviates too far from the visual canon established by Bungie. The bulky depictions of Elites and Grunts scarcely resemble their canon appearances.

Manual vs Books
(These discrepancies are created when material from the game manuals is inconsistent with material from the novels.)


 * The Halo: Combat Evolved Manual states that the Harvest incident took place in 2520, while all other sources specify 2525.
 * The manual also states that Captain Keyes has served in the UNSC since 2526, though he was fresh out of the UNSC OCS in 2517.
 * The Grunts are referred to as being five feet tall, but in The Fall of Reach, they are referred to as being a meter tall (a little over three feet).
 * In Halo: The Flood, the Chief spots some 12-gauge shotgun shells near an entrance. In the manual, they are said to be 8-gauge.

Game vs Books
(These are created when the novels describe events that are not the same as what is seen in gameplay. As explained in this forum post, the games are considered by Bungie to be more canon.)


 * Jackals and Special Ops Elites are on board the Pillar of Autumn. This does not occur during gameplay on any difficulty.
 * The primary insertion group during the Truth and Reconciliation assault is made up of ODSTs, while in-game there are only Marines. ODST's did appear in Halo: Combat Evolved (contrary to popular belief), although they did not wear ODST Body Suits in that game. These could have been separate insertions, but a singular attack is more likely.
 * Cortana identifies Halo in Halo: The Flood when escaping the Pillar of Autumn, but it isn't identified until the level Truth and Reconciliation in the game.
 * Halo: The Flood describes only four Scorpion tanks being retrieved from the Pillar of Autumn, which does not account for the one in Assault on the Control Room. Fire Team Zulu was working out of Alpha Base, so they could have been ordered to bring the tank, which would account for it being near a downed dropship.
 * Cortana accesses Halo's Control Center by having the Master Chief remove the memory chip from his helmet and place it in the console, while in the novel she broadcasts herself into the system using the suit's transmitter.
 * UNSC ships use rotating sections to simulate gravity yet no such mechanism is seen in-game. This could be accounted for if the rotating parts were inside the ship. The Pillar of Autumn may also have been using the reverse-engineered Covenant technology called Gravity Plating instead of rotating sections.
 * The Pillar of Autumn's MAC cannon is depolarized and cannot fire, yet the gun is apparently used, and the loss of fire control still makes headlines (H: CE, opening cinematic).
 * The cutscene in H1 at the end of the level "The Pillar of Autumn" clearly shows the Autumn being fired upon with plasma. However, in the novel, the Prophet at the ring forbids the Covenant ships to fire, lest they strike the "sacred relic". However, the order could have been ignored or overruled (perhaps by the Supreme Commander to stop the Autumn from hitting the surface, as the Prophet's demand was made before the ship was even boarded.)
 * Grunts love to overcharge their plasma pistols in the books, yet they never do so in the games.
 * In the game, Master Chief throws Pvt. Jenkins' Record View away, but he still has it in First Strike. This could be explained by the Chief's suit automatically making a copy of Jenkins' recording as a possible means of gathering intelligence, like today’s armed forces gathering dog tags from the dead, although this is only a theory.
 * On several occasions in the books (too numerous to list), UNSC forces are mentioned as switching their MA5Bs from bursts to full auto, although in the games, they are only capable of fully automatic fire. Likewise, in First Strike, Vinh fires two single shots at an Elite with her BR55.
 * In the Halo Graphic Novel -- specifically the Last Voyage of the Infinite Succor -- the Flood are shown consuming every possible living creature they can find, yet in the games, it seems that they are only interested in intelligent beings. Additionally, the Halo Array was mentioned as only being able to kill beings with sufficient biomass and intelligence to support the Flood. However, the Flood was in its feral stage, and could have been searching for more calcium to sustain its Proto-Gravemind.
 * In the game Halo 3, under the Multiplayer Armor Permutations menu, it states that the ODST helmets were used for the Spartans to train in. However, this is never mentioned in Halo: The Fall of Reach. It may have been omitted, however, as large sections of the training are missing from the book.
 * In Halo: The Flood, most of the Marines described in the book were female, despite no female marines being in Halo: Combat Evolved at all.
 * In Halo 2, Cortana says that the Covenant didn't expect humanity to be on Earth, but in Halo: First Strike, immediately prior to the First Battle of Earth, the Covenant clearly knew that humanity was on Earth, and had a gigantic fleet to deal with it.

Books vs Books
(These errors happen when information from some of the novels is inconsistent with information from other novels.)


 * 33 SPARTAN-IIs successfully adapted to the augmentations, but there have been too many listed. Kurt-051, Sheila, and Randall were listed as MIA before 2552, as were Jai-006, Adriana-111, and Mike. Samuel-034 and three other Spartans were KIA, and one WIA , but thirty SPARTAN-IIs were present to defend Reach (John-117, Linda-058, James, and twenty-seven of Red Team), when there should have been only twenty-two (or possibly only nineteen, as it is unknown whether Jerome-092, Alice-130, and Douglas-042 returned to UNSC-controlled space).
 * Pelican's operational maximum is listed as 12 Marines, elsewhere as 3 crew, 10 seated, 5 standing , yet still elsewhere they can carry 75 children , 30 Elites , or 27 Spartans . It should be noted, though, that the Pelican in Halo: First Strike has all the unnecessary equipment removed -- likely including the seats -- and the Spartans are more or less jam-packed into the small craft.
 * It is possible, that there may be different variations of Pelicans though we only see the one type in game, or that these were equipped with some kind of troop bay extension.
 * During the Battle of Reach, many Covenant ships are destroyed, but not before they can loose their own lethal plasma attacks. However, later plasma en route to a target merely dissipates as the originating ship and its magnetic controls are destroyed. It is possible that the magnetic controls were not destroyed in the former instance, allowing the plasma to continue to its target.
 * Halo: The Fall of Reach states that Harvest has a population of 3 million. However, in Halo: Contact Harvest, it is stated to have a little over 300,000.
 * Lieutenants Hall and Dominique are introduced as members of the command crew of the Pillar of Autumn, but are absent when the ship arrives at Installation 04. It should be noted, though, that Halo: The Fall of Reach states that there was a flutter in Dominique's heart when he came out of cryosleep prior to the discovery of Alpha Halo, perhaps indicating cardiac arrest.
 * Engineers are supposedly first seen by humans during the Battle Of Sigma Octanus IV in 2552. However, in Halo: Ghosts Of Onyx, when Kurt is reviewing a mission of the SPARTAN-IIIs some years prior to that battle, he saw Engineers. Such information could have been kept classified by the ONI due to the secrecy of the SPARTAN III program. Engineers are also occasionally seen in the campaign of Halo Wars, which takes place in 2531.
 * Chronologically, the first time Brutes are encountered by the UNSC was at the Battle of Harvest in 2525, yet the Master Chief has no intelligence on them until the attack on the Unyielding Hierophant in 2552. This could be accounted for by the secrecy of the first encounter with the Covenant, as ONI could have tried to cover up the failure of the negotiations with the Brutes. Like the Huragok, Brutes are also seen during the events of Halo Wars.
 * In 2525, when Harvest was glassed by the Covenant, UNSC technology took approximately two months to traverse between Harvest and Reach, but in 2552 it takes a ship only 19 days to travel between Reach and Earth, when the distances between the three planets are only between 10 and 11 light years.
 * Throughout Halo: Ghosts of Onyx, Elites referred to superiors as "sir", while in Halo: The Flood, they said "Excellency". It is possible, though, that the two words are English translations of the same Sangheili phrase.
 * In Halo: First Strike, Dr. Halsey puts 4 sub-machine guns and 16 clips of ammunition in a bag. In Halo: Ghosts of Onyx, Kelly found the same weapons, but they were 4 MA5B Assault Rifles.
 * The BR55 (Battle Rifle) is said to be a prototype weapon on the planet Harvest for Captain Ponder's militia in Halo: Contact Harvest. However, in Halo: First Strike, some thirty years later, the SPARTAN IIs only just get the weapons, despite being the top choice to receive the weapons.
 * Jai remembers being abducted and brought to Reach along with seventy-five other children. In fact, there would have only been seventy-four other children.
 * Prior to 2525, UNSC ships used rotating sections to simulate gravity, and the Spartan-II's were surprised to discover artificial gravity on the Covenant ship they boarded. However, since then, multiple human facilities and ships are shown to have artificial gravity capability. It is possible that this technology was adapted from the Covenant, but that is unlikely due to the difficulty in capturing intact Covenant ships, much less reverse-engineering them. The most likely possibility is that the writers use anti-gravity technology for convenience purposes. It is also possible, though, that the rotating sections exist between the walls and outer hulls of UNSC vessels.
 * When Lieutenant Keyes is warned of the incoming Covenant fleet and asks what UNSC ships are nearby in Halo: The Cole Protocol, the book first states that three Destroyers are picketing, but immediately counters that the and three frigates wouldn't be able to repel a Covenant assault. However, they are later confirmed to be Destroyers, one of which is the Do You Feel Lucky?.
 * Chief Petty Officer Mendez remarks that some of the Alpha Company candidates were orphaned at Jericho VII. His speech takes place on December 12, 2531, yet Jericho VII was not glassed until the February of 2535.
 * In Halo Wars: Genesis, Ellen Anders mentions the planet Onyx in passing, while giving a talk about an alien prescence. However, in Ghosts of Onyx, Kurt reads a file that says Onyx has been classified since 2511. Genisis takes place in around 2531.

Game vs Game
(This occurs when information from one game is not consistent with information from another.)
 * In Halo: CE, the Master Chief needs a chip to house Cortana. In Halo 2, all he needs to do is touch something to allow her to move from his suit to another power source. It is reverted back to the chip in Halo 3, however, it gains some of the properties of the touch ability in Halo 2. Why technology went backwards in between Halo 2 and 3 is unknown. Although this could be because the suit might interface differently with a bomb as opposed to Halo's control center,or because Master Chief's Armor suit was damaged in the fall from the Forerunner Ship to Earth


 * In Halo: CE, the Sniper Rifle had night vision, but it is absent from Halo 2 and Halo 3. This is likely due to its limited purposes, but it is still strange to see a weapon losing an advantage, and the different versions of the Sniper Rifles during the era could not be accounted for that loss.


 * The doors in High Charity are different in Halo 2 and Halo 3. This could be because the High Charity part of Halo 2 takes place near the Prophets' Sanctum, and in Halo 3, near the core area so there is a difference in design.