Berserkir logo and brand name.
Berserkers (or berserks) were champion Norse warriors who are primarily reported in Icelandic literature to have fought in a trance-like fury, a characteristic which later gave rise to the English word berserk. These champions would often go into battle without mail-coats; the word “berserk” meant going into battle wearing only wolf pelts or other animal skins. Berserkers are attested to in numerous Old Norse sources, as were the Ulfhednar (wolf-coats).
The English word berserker is derived from the Old Norse words ber-serkr (plural ber-serkir) <…>.