Shin'etsu Kisaragi

Shin'etsu Kisaragi was a shinigami and the father of Shūsuke Amagai, little is known about him, but he was killed by Shigekuni Yamamoto-Genryūsai as he knew about the knowledge of the bakkoutou, and Yamamoto's possible involvement with the Kasumiōji clan to secretly allow them to create bakkoutou. As a result, Shūsuke Amagai fraguates a plan against Soul Society to avenge his father.