Kuu is Hajime's cat that serves as a "police cat" of sorts. Hajime keeps him in the guard room of Nanba Prison since he can't have pets at his apartment. The cat tends to follow Hajime or Jyugo around everywhere.
Kuu is a fluffy black cat with green sclera. He has a scar over his left eye, resembling Hajime's. He wears a black hat with a gold C and braiding on it. It is similar to the uniform caps worn by the prison guards.
He seem to act very friendly. He's often seen following Hajime & Jyugo. Jyugo claimed he's the only guard that he cannot out run.
- "Kuu" means "nine."
- Kuu's favorite color is dark red.