From Lexicanum

Berserkers are Chaos Space Marines dedicated entirely to glorifying the Chaos God Khorne through hand to hand combat. Driven by bloodlust, their only purpose is to kill and destroy their enemies in the name of Khorne. Eschewing long ranged weaponry, Berzerkers make almost exclusive use of close combat weapons, in particular the chainaxe. However, they are known to use almost anything as a weapon at times, often continuing fighting even when in possession of no offensive weapons other than their own bodies.

History

The original Berzerkers came from the World Eaters Legion led by Angron, who turned to worshipping the Blood God once they renounced the Emperor; however, Marines from other Legions and more recently turned Renegade chapters, also took to Khorne worship, becoming Khornate Berserkers.

Strengths and Weaknesses

Khorne Berzerkers are rightly feared by friend and foe alike, and in accordance with their will to please the god of war Berzerkers find the need to spill "Blood for the Blood God" overpowering. They are known to kill even their own allies if caught in the heat of battle or lacking alternative adversaries, a situation epitomised by Kharn the Betrayer. Their battle prowess has earned them a fearsome reputation on the battlefield, although it also leads to them being unable to form a single, cohesive and mutually supportive unit. Berzerker bands vary in size and strength, often lending their aid to whichever side offers them the greatest chance of combat and slaughter.

Sources

• Codex: Space Marines (3rd Edition, 1st Codex)
• Galaxy in Flames (Horus Heresy Series) by Ben Counter