Ittō-ryū member of great height (over 1.90 meters/6'2" tall). Unlike most members of the Ittō-ryū, Isaku has no weapons to speak of, instead he wears various piece of armor and tends to act defensively. He is also Doa's best friend and the two always travel together. Isaku often finds himself rescuing Doa, apologizing for her and keeping her from killing others (usually by picking her up and running away). He and Doa have also developed complementary fighting styles, with Isaku acting as the defense and Doa as the offense. He ends up befriending Asano Rin. Is also Christian and was the son of a Christian priest. He is not incredibly intelligent, but is kindhearted. He has been cutted in two as a result of the experiments in Habaki's compound, only to be reassembled by Doa - he has had similar regenerative abilities to Manji, but lost them after some time has passed.

(Source: Wikipedia)