Kill Riurry is a quest given by Yrruir, the greater white unicorn. The quest is to 'simply' find and kill her evil counterpart Riurry the greater black unicorn, and return to her. The reward for completing the quest is a once-off complete removal of all corruptions the PC has acquired. Note that if Riurry is generated non-hostile and talked to, he will offer a quest to Kill Yrruir.