The protagonist's cousin. Since his parents died when he was very young, he was taken care of by the protagonist's family. He lived with them until last year, but nowadays lives by himself in Aoyama. He's the character who gave the protagonist the COMP with the installed "Demon Summoning Program". He's considered a genius programmer in his field. In Amane and Naoya's endings, it is revealed that he is the reincarnation of the biblical Cain, thus making him the Hero's brother. He is voiced by Kamiya Hiroshi in the Drama CD.