berserk

Adjective

• frenzied as if possessed by a demon
  • the soldier was completely amuck
    
  • berserk with grief
    
  • a berserk worker smashing windows
    

Noun

• one of the ancient Norse warriors legendary for working themselves into a frenzy before a battle and fighting with reckless savagery and insane fury

Related words

• Synonyms: 
  amuck , amok , demoniac , demoniacal , possessed(p) , berserker