Nu-13 is a Murakumo Unit said to be the Sword of Izanami. While she was in a flower field, Pandora came to Nu and brought her to Viperia, where she escaped along with Sachiko, Eze and Leafa. Worried about her tendencies, especially since she hasn't learned to channel her new emotions yet, the Hero Alliance turned to Hope, who recruited her so that he could be a positive influence in her life.