(from Old Norse beserkr , "bearskin") In premedieval and medieval Norse and Germanic history and folklore, any member of unruly warrior gangs that worshiped Odin and attached themselves to royal and noble courts as bodyguards and shock troops.
They raped and murdered at will in their host communities, and their savagery in battle and animal-skin attire (they are also said to have fought naked) contributed to the development of the werewolf legend in Europe.