Isaku Yasonokami  

, 八苑狼 夷作

Isaku is an Ittō-ryū member who stands over 1.90 meters tall and lacks weapons. Instead of carrying arms, he wears protective gear and adopts a defensive stance. Unlike other members of the Ittō-ryū, Isaku is best friends with Doa, whom he rescues from danger and apologizes for. They have complementary fighting styles, with Isaku acting as defense while Doa focuses on offense. Despite not being particularly intelligent, Isaku is kindhearted. He was once a Christian priest's son and has been cut in two during experiments at Habakis compound. After being reassembled by Doa, he regained some regenerative abilities similar to Manji but lost them over time.