|Japanese name:||海堂 貴緒|
Despite his early presence as a character who exists solely to create a lighter atmosphere among a very dark story, he gradually gains depth as the story progresses. He becomes a loud voice that champions pacifism and self-worth. This contrasts strongly against Soubi's submissive nature that willingly accepts violent treatment and strongly desires to be completely controlled, albeit from only very certain people. More significantly, Kio's views are shared by Ritsuka. Together, they provide a very black-and-white atmosphere that allows only one line of thinking.
It was recently revealed that Soubi only became interested in Kio because of a tattoo on his back, and a vow that he took when he got it.
He has a daughter that looks to be around ten years old; she notably has no cat ears. A twin sister also appeared but he had no knowledge of her.