Rin is the only survivor of the battle against the demon tribe 800 years ago. She is an Idaten and the one who "summoned" Hayato and Prontea. She has been training Hayato and the others while guarding the seal that trapped the demon tribe.

Her training is brutal, and it involves beating Hayato and the rest to near death. She usually stays around the seal, but sometimes travels quickly around the world looking for summoning spots. She is currently the strongest Idaten alive.