Shin'etsu Kisaragi

was a Shinigami from the First Division and the father of Shūsuke Amagai.

Appearance
Similar to his son, Shin'etsu wears his dark brown hair in a messy fashion. As a seated member, he wore the standard Shinigami uniform, albeit, in the flashback it was tattered.

History
When the Kasumiōji clan began manufacturing the Bakkōtō, Central 46 denied captain Genryūsai Shigekuni Yamamoto's request to investigate the compound. Nonetheless, Shin'etsu offered to sneak in anyway. While there, Gyōkaku Kumoi found him and forced a Bakkōtō on him. Kumoi then ordered for him to kill the person that sent him. He returns to Yamamoto, but his captain unleashes his Shikai to defend himself. Despite his hesitation, he kills Shin'etsu. Shūsuke finds his dying body and hears his father's last words, "Beware the Bakkōtō".

Synopsis
Shūsuke worked with Kumoi for years and gained a Bakkōtō of his own so that, someday, he could kill Yamamoto as revenge. However, Ichigo stops him and Yoruichi Shihōin explains the truth about his father. In response, Shūsuke lets the fire of his Zanpakutō consume him.

Zanpakutō
Despite having a Zanpakutō, it was never revealed if he could use Shikai.

Bakkōtō
Upon being captured by the Kumoi, he was forcibly given an experimental Bakkōtō. It has two curved extensions on either end of the blade, that take the appearance of a hook. Its powers, if any, are unknown.