A handsome young wealthy nobleman, main opponent of series. He is the leader of the government's Demon Extermination Squad. Raikou Minamoto wants to make Kantarou cancel his name contract with Haruka so Haruka will get his memories back and become the "real" demon eating tengu that he wishes to defeat. He hates that Kantarou was able to unseal the demon-eating tengu but he himself could not do so. He wields Minamoto's Legendary sword. His allies are Watanabe and Ibaragi.