Design based on one of the four Rook "Berserker" pieces from The Lewis Chessmen.
The Berserkers (Old Norse: berserkir) is attested by the 13th century scholar and historian Snorri Sturluson as "bare", which he understood to mean that the warriors went into battle bare-chested, or without armour. However in the saga of King Hrólfr Kraki, a berserker who is able to shape-shift into a bear and uses this ability to fight for king Hrólfr Kraki. "Men saw that a great bear went before King Hrolf's men, keeping always near the king. He slew more men with his fore paws than any five of the king's champions." The wild fury shown on the Rook pieces and the biting of the shields lends further credence to the Berserker theory.