The Flood, referred by the Covenant as the Parasite, are a species of highly virulent parasitic organisms that can reproduce and grow by consuming sentient life forms of sufficient biomass and cognitive capability. The Flood can infect and mutate humans and Covenant species, such as Unggoy, Kig-Yar, T'vaoan, Sangheili, and Jiralhanae.

Overview and Background

The Flood are an extremely adaptable, dangerous, and expendable parasitic life form.

They were first encountered in the Milky Way galaxy by an Ancient Human empire 10,000 years prior to the Forerunner-Flood war. The earliest known instance of the highly infectious viral super cell later known as The Flood form to be encountered came in a fine desiccated powder, contained in cylinders. This powder was actually Precursor remains.

Flood Forms, Weaponry and Equipment

While they don't use a rank structure, there are a variety of types and Combat Forms.

Form Image Description
Proto-Gravemind The Proto-Gravemind, also known as the Proto-Compound Intelligence, is an advanced Flood form created from the biomass of the most intelligent living organisms available, with the ultimate goal of creating a fully-functional Gravemind. Only one Proto-Gravemind is encountered in SPV3.
Combat Form A Flood Combat Form is a sentient being that has been infected by the Flood parasite via an Infection Form or Flood Spores, mutating the victim into a basic combat unit for use by the Flood. They are extremely dangerous, but can be easily defeated when alone or feral. However, when under the control of a Proto-Gravemind they can be coordinated and deadly.
Combat Carrier Form The Combat Carrier Form is a sentient being infected by the Flood Infection Forms and serves as a basic combat unit and transporting Infection Forms. Two types have been encountered, the ODST and Elite Combat Carrier Forms.
Ranged Carrier Form The Ranged Carrier Form is a type of Combat Carrier Form with the natural ability of mid to long range combat without the use of weapons. The only known host that produces such a flood form are the Blind Wolves that naturally inhabit the Halo ring.
Carrier Form The Carrier Form is a type of Flood form primarily used to both create and transport Infection Forms thus effectively spreading the Flood infection. There are two known types, the Grunt Carrier and the Jackal Carrier.
Infection Form The Flood Infection Form is the basic and first stage of the virulent Flood xenoform. It is the most commonly seen stage of the Flood, and is the form responsible for spreading the Flood infection.

Gameplay Information


In Halo: Combat Evolved, the Flood were notorious for their erratic style of combat. They would bum rush enemies, and the player, firing their weapons with no regard for their own well being. Many players don't enjoy fighting them for their lack of in-game intellect. SPV3 addresses this issue by adding new types of Flood enemies, introducing factors that welcome new strategies, creating new AI's and altering existing ones for them.

Since there are now more types of Covenant and Marines, there are more types of Flood. Due to the changes made by CMT, Combat Forms will generally, though not as intelligently as uninfected enemies and allies, act like whatever hosts they have infected. Their zombie-like behavior is still embedded in them as a faction, however: Human Combat Forms are fewer in number, since there are less humans than Covenant on Halo, and usually hang back and shoot enemies at a distance with mid to long range weapons, like living Marines would. Elite Combat Forms now have energy shields left over from the combat harnesses of their Sangheili hosts. They have a more tactical method of combat than they did in CE, slowly advancing on an enemy, hanging back behind lesser Flood forms and even using their weapons alternate method of fire if available, eg: the Plasma Pistols charged shot. They also know to seek cover when their shields are down and let them recharge. The colour of their armor reflects the energy shield strength associated with living Elites. Carrier Forms, now identified as infected Grunts, act as they did before, but are not instant kills when they explode next to players and release a lot more Infection Forms.

Infection Forms are much higher in number than in Halo: Combat Evolved, and have the added ability to infect living hosts on the spot in real time, adding extra factors to decision making in the game. Flood forms created from Infection Forms on the field are determinant to the NPC being infected. The only enemies in the game that can't be infected are Hunters, Sentinels, Enforcers and Hero Units. Contradictory to other games, they also can't infect corpses or reanimate dead Flood forms, possibly for fairness of gameplay reasons since dead bodies can't be destroyed in SPV3.

Because of the new infection ability of the Infection Forms, new enemy units for the Flood were created from scratch for SPV3 by CMT. Jackals, Skirmishers and Brutes can also be infected by the Flood. Jackal/Skirmisher Combat Carrier Forms are spider-like in appearance, walking on all fours. They are somewhat similar to the Stalker Pure Flood Form from Halo 3. They leap at enemies to attack them at close range, but are very easy kill. They will explode into several Infection Forms when killed. Brute Combat Forms differ in appearance from other Combat Forms, having a pincer like appendage on their left arm in favour of the tentacle like claws seen on other Flood forms. They essentially act identical to the Flood seen in CE, mirroring the Brutes aggressive nature, possessing no A.I. quirks or shielding of any kind. However, one particular Brute Combat Form is encountered as a one time enemy in The Commander and is equipped with Brute Power Armour. Despite this, it is still easy to dispatch.

New types of Elite and Human Flood forms also exists. Elite and ODST Combat Carrier Forms, like the Jackal Combat Carrier Form, explode into Infection Forms after being dispatched. They are easily recognizable due to the enormous, bludging, yellow, sack-like cysts on their backs. Elite Combat Carrier Forms usually don't carry weapons, but move much faster than any other enemy in the game. The ODST Combat Carrier Form acts much like the Marine Combat Form, only it is immune to headshots (see Developer Information).

The Blind Wolves found in missions like Halo and The Silent Cartographer: Evolved, are featured in the missions None Left Behind and The Commander: Evolved as Flood forms. They are unique as they don't carry weapons but are armed with natural projectiles, reminiscent of the Ranged Pure Flood Forms of Halo 3. They are fairly tough as the weak spot where the Infection Form resides is in their mouth, protected by their top jaw (see Developer Information). Upon death, they also release more Infection Forms.

Flood growth pods are also a feature of the Flood in SPV3. They usually appear in areas where the Flood infestation is deep rooted. Damaged Combat Forms are stored inside them to heal but they are also used as incubation pods for Infection Forms. Growth pods come in different shapes and sizes and will explode if players get near, but not all pods. A small number of pods throughout the campaign will only erupt if players shoot them, but it is impossible to tell which is which unless they are left alone. Others may remain dormant but release Combat or Infection Forms if their location is revisited.


Since the Flood will appear in high numbers, the best strategy would be to use the Cluster Grenade or Fragmentation Grenade as soon as Combat Forms touchdown from where they spawn. If you have the Brute Plasma Pistol present, the overcharged shot can help take out many Combat Forms instantly, since the flames can cause whatever grenades they drop to explode. The M7057 Flamethrower, Sentinel Beam and Sentinel Sniper Beam are also very effective for this strategy against the Flood, especially in narrow areas, like in The Maw, due to their incineration effect. The Flamethrower will also quickly burn through an Elite Combat Form's shields. The M247 Machine Gun's high magazine can help to take down many Flood forms from a distance while the M91 Shotgun can do the same in close quarters. Any headshot weapon can be used to shoot the Infection Form that is controlling the Combat Form, resulting in an instant death (see Developer Information).

Developer Information

All Flood forms (with the exception of the Grunt Carrier Form, Elite and ODST Combat Carrier Forms) have a region on their body where the Infection Form controlling it can be destroyed, similar as to how the headshot region works in Halo 2 and Halo 3. The difference here is that the region will have a high multiplier for all damage, and Flood health can be manipulated so that damage to them will often result in them feigning death, with the Infection Forms destruction resulting in their true death. Certain damages such as the Brute Shot, melees, and explosives will cause enough damage to create a true death as well. A player using, say, an Assault Rifle or Plasma Rifle can fire in bursts to take down the Infection Form controlling the Combat Forms, giving the player some more strategies than just pumping the Combat Forms full of bullets. All units have their own unique modified health systems.


  • Infected Jackal Forms don't appear in other Halo game other than Halo Wars.
  • In Halo lore, Jackals technically can't be used for Combat Forms by the Flood due to their lack in calcium.
  • A rare, but possible sight in SPV3 is to see a Combat Form, usually Marine, that will not physically die no matter how much damage is inflicted. It's likely that this may simply be a minor glitch as it won't appear on the radar nor will other enemies acknowledge it.
  • Along with Combat Evolved's subtle gurgling and croaking sounds the Flood make, the screeches, howls and roars they emit from Halo 2 and 3 have been added to them in SPV3.
    • Before SPV3.2, Jackal Combat Carrier Forms emitted different noises, producing high-pitched, over-powering cry's and screeches. CMT altered them to sound like other Flood forms in SPV3.2, most likely due to complaints from players saying that the sound was very annoying.
  • The Flood buddy glitch is still possible in SPV3.
  • Characteristics of the Elite Combat Carrier Form resemble the Elite Combat Forms appearance in Halo CE.
  • Carrier forms actually come from infected Marines; however, Grunts are now used as incubators for the Flood. Although Lieutenant McKay theorized that Grunts aren't used for combat but instead for Carrier Forms, her theory was not true.
  • One of the main inspirations for the Flood seems to be from the 1982 film The Thing, where similar extreme and gruesome mutations befall a group of people when they are attacked by an alien parasite.



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