 He eventually chews through the post his is chained to and kills his owner in a fit of rage referred to as the White Fire.Rolv is the only Wolperting in the novel that references the White Fire so it can be assumed that it is exclusive to him and not a common trait of all Wolpertings, but it appears to be a brief berserker period in which his innate talent for fighting takes complete control of his consciousness until his opponent is dead.As such, Rolv must suppress the White Fire against opponents he doesn't want to kill.