The Abnormalities are victims of psychic energy research experiments conducted by Trilobite Energy Corporation (TEC for short).
Formerly human, the Abnormalities now live up to their namesake, being highly aggressive and no longer acting on reason or thought and are improved variants of The Infected.
Abnormalities were first reported during the investigation of Outpost 31 conducted by the WarCorp, an area under TEC's ownership. The WarCorp fireteam engaged and presumably wiped them out, leaving no surviving Abnormality to leave the facility.
However, even with the Abnormalities eliminated and the DM-09 samples destroyed, TEC managed to secure all other samples and is possibly planning to conduct another experiment to create more. How they plan to do so and whether or not more abnormalities will appear are currently unknown.
Like the Infected, there are multiple types of Abnormalities:
- Dr. MG (boss)
Transformation into an Abnormality
It is not clear how exactly how a person turns into an abnormality, but it is heavily implied that direct exposure to the DM-09 chemical results in someone turning into one. And since the mercenaries sent to raid and investigate Outpost 31 survived from prolonged exposure and physical interactions from the abnormalities, it can also be inferred that the chemical cannot spread from one person to another through bites or scratches, unlike how the Infected spreads the virus.
- The Abnormalities are the fourth faction to be encountered in Fireteam.
- Abnormalities resemble frostbitten Mauler Infected, the only difference being the skin color which is blue instead of red.
- Some of the Abnormalities are using cosmetic items.
- Abnormalities are the first NPCs that use the Infected crouch animation to move, essentially making them crawl.
- Abnormalities are the first characters in the game to bleed a different color of blood. They bleed blue blood when shot.