From Halopedia, the Halo wiki
The most violent members of the Banished military, Jiralhanae Berserkers gave over rational thinking in order to destroy their enemies. In the smog-filled barrens of Warial’s Doda’keyt the Berserkers who had sworn loyalty to Atriox, all proceeded to consume an unstable stim which suppressed all rational thinking and drove them insane. The Jiralhanae Berserkers are filled with unbridled anger and seek only to bathe the blood of their enemies. Numerous Jiralhanae Berserkers participated in the Battle for Zeta Halo. Notably, the first Jiralhanae that Master Chief John-117 encountered while aboard the Ghost of Gbraakon was a Berserker who confronted him in a corridor outside the control room for Hangar One.
Berserkers can be distinguished by their hunched posture, even when at ease, and mouth-covering armor. When they spot an enemy, they will roar and run towards it at high speed. They wield no guns, but strike using their fists, both with running haymakers and quick swipes and throw dynamo grenades to stun their enemies and make them easier targets. They roar almost constantly, and their position can be determined by an attentive ear.
For protection, their armor provides them moderate resilience, and their mouthpiece must be shot off before allowing headshots. They come in two ranks, red armored and black armored with Jiralhanae energy shielding for additional protection.
The wrist blades on their arms can be shot off. However, this does not affect the amount of damage they deal with their melee attacks.
List of appearances