The heroine is first named as simply the partner character in the hero's game of Devil Busters. In the real world, however, she is a witch who served under Pazuzu and was paired with the demon Orthrus. After the hero and his friend defeat Nebiros, Pazuzu instructs her to give them the Flame Talisman via the friend's girlfriend, Hiroko. Shortly after this, she deduces that Pazuzu was simply using her and the heroes to wrest control over Tokyo from Bael, and breaks away from Orthrus, taking up residence in the Tokyo Tower. There, she becomes known as a healer and protector of the people living in the ruins of Tokyo, who claimed that she was blessed by Izanami.
Later, Pazuzu sends the heroes with Orthrus to defeat her for her treachery, but during the resulting confrontation, she manages to get the hero to agree with her viewpoint. Angered that the hero would side with her over him, the friend leaves with Orthrus, vowing if they cross paths again, they'd be enemies. She regrets that the friend failed to see the truth, but expresses her hopes that he would eventually come around. After this, she becomes the hero's companion and travels alongside him throughout his journey to save the world from the demons. Much later on in the story they reach Astaroth's Castle in the Forest of Confusion, the partner is captured by Astaroth, but is later saved by the hero.