Those turned to beasts by the berserker creed often cannot return to their normal selves. On the signal of the lightning, they go into battle and fight until utterly exhausted.
Berserkers (or berserks) were Norse warriors who are reported in the Old Norse literature to have fought in a nearly uncontrollable, trance-like fury, a characteristic which later gave rise to the English word berserk. Berserkers are attested to in numerous Old Norse sources. Most historians believe that berserkers worked themselves into a rage before battle, but some think that they might have consumed drugged foods.
4-5, 7-2, 7-3, 7-4, 8-1, 8-3, 9-4, 10-4, 13-1, 21-1