The special captain of the third unit of the Shinsengumi. He is the sole constant member of the third unit as all of the others were cut down for treason.
He never speaks, leading himself to a multitude of misunderstandings and unintentional intimidation. In writing he ends all of his sentences with "Z", the sound he makes while sleeping.
He is trusting to a fault, considering Katsura to be his good friend despite his overtly duplicitous nature.