Berserker

n. ancient Norse warrior known for savagery and reckless frenzy in battle

For other uses of the term, see Berserker (disambiguation) and Berserk (disambiguation). Berserkers (or Berserks) were Norse warriors who were commonly understood to have fought in an uncontrollable rage or trance of fury; the berserkergang.The Úlfhéðnar (singular Úlfhéðinn) mentioned in the Vatnsdœla saga, Haraldskvæði and the Völsunga saga were said to wear the pelt of a wolf upon their heads when they entered battle. (For example: Warinhari, Haimric, Theudberga, Hlodwig etc.)
See more at Wikipedia.org...

Noun
1. one of the ancient Norse warriors legendary for working themselves into a frenzy before a battle and fighting with reckless savagery and insane fury
(synonym) berserk
(hypernym) Scandinavian, Norse, Northman

n. madman, mentally insane man

(n.)
One who fights as if frenzied, like a Berserker.
  

(n.)
One of a class of legendary heroes, who fought frenzied by intoxicating liquors, and naked, regardless of wounds.