Keita is the male lead of the show. He was considered a failure by his family due to his attitude towards their ancient duty to vanquish evil, treating it like a parttime job, and his initial inability to find an Inukami to bond with. Even though Yôko becomes his inukami and is fully interested in him, he has a bad habit of flirting with other girls; it is later revealed that Keita is mortified by the thought that, if he should develop a relationship with Yôko, he might become the father of a litter of puppies, rather than of a human baby. He is frequently punished for his transgressions by Yôko, to whom he had to promise that he would be loyal to her, that he would be hers and that he would be her toy, to do with whatever she wanted, before she would contract with him. He wears a dog's collar as a symbol of this pact - an item he originally intended as his 'vow gift' to Yôko. Yôko has frequently landed him in jail by teleporting him into a public place without his clothes, causing him to be mistaken for a streaker and arrested for indecent exposure. Due to this, he has been named Ra-ou (Naked King) by the city's perverts (male and female alike).

Keita possesses considerable athletic skills, can make frog-shaped talismans up to around the size of his fist from rubber which he can use to make ranged attacks and is a practitioner of xingyiquan. However, a shinigami named 'Sea of Violence' commented his martial arts skill lack style. Despite his many flaws, Keita has considerable redeeming qualities; he is determined, usually fearless and loyal to his friends and to people under his protection.