Trigens are primates and/or humans that have been genetically altered by Dr. Krieger and his scientists in the testing of a mutagen designed to enhance the strength, speed, and endurance of humans. The experiments yielded good results in terms of strength and speed enhancement, but the mutation had a horrific side effect; all Trigens become horribly deformed beasts, and their minds are torn apart by an overwhelming primal urge to kill and feed.

They were at first kept in containment areas and cages in various installations throughout the islands, but were able to escape (and, in some cases, were intentionally turned loose). There are five types of Trigens, of which two are chimpanzees and gorillas, and three are derived from humans. There is also one "failed" variant of Trigen which is seen twice, once in the Bunker and once in a test facility.

Trigens have a simple hierarchy based on size. Bigger Trigens will give orders to smaller Trigens when searching for Jack.

Non-Human Trigens Edit

Monkeys Edit

These Trigens, dubbed 'monkeys' by Jack, come in two variants; One is a chimpanzee mutant, and one a gorilla mutant. Chimps are small, but can shred through even a fully healed and armored Jack with just a few slashes, and are incredibly fast. They can leap upon a foe from meters away. The eyes of chimps cannot be seen, as they are covered in a layer of skin, have huge maws, and hairy backs. Gorillas are slower and cannot jump as chimps can, but are slightly more tough and deal a bit more damage per swipe. They are able to pounce upon foes once they get close enough. Gorillas are totally hairless, their jaws are fused with their chests, and their deformed faces have bulging bloodshot eyes.

BerzerkerEdit

Mutant Screwed is only seen in Bunker on a table and it is the biggest mutant, with a big kind of knife on the right arm and a hand on the left one. It also has a big mouth on the face. It is a Monkey, Big and a human in one. The Mutant Screwed is in the game, but was never used, although you can see it in a cutscene when Kriger kicks Jack out of the Troopgunship. You can place Mutant Screwed in the sandbox editor but it has no animations.

Human Trigens Edit

Locusts Edit

Locusts are tall Trigens with abnormally large and muscular legs. They normally carry fully automatic AG36 rifles, and have the ability to leap incredible distances. They move quite fast, and will swipe at enemies that get too close.

Spectres Edit

These Trigens are fitted with experimental cloaking devices that allow them to become completely invisible, and they put this to good use. They will often remain cloaked until they are killed, but using the biothermal CryVision goggles makes them light right up. They are armed with silenced MP5s, and will claw enemies that get close.

Fat Boys Edit

These big, hugely muscular Trigens, called Fat Boys by the mercs, are extremely tough. Most times when they are encountered their right arms are mounted with missile launchers, but sometimes they are encountered with just their bare hands to fight with. When Jack gets too close, they will strike him with their claws and kill him instantly. Fat Boys have a glowing implant in their chests that devastates them when it is shot. These are the only Trigens that ever speak, and they will growl things such as "You're goin' down!" and "Die!" when in combat. They are the stupidest of all the Trigens, as best seen in the occasional instances where they may get stuck in a doorway and instead of taking another way around, will attempt to get free and kill Jack by repeatedly firing their launcher, killing themselves with a blast to the face from their own missiles in the process, since their shoulders are too wide to allow their arms (and thus the launcher) to fit through a doorway. If presented with a situation in which they cannot reach Jack, they will simply shoot in his general direction until something happens. They never flank enemies and always go for them head on. They are characterized by their loud, lumbering footsteps.