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 Shingiami uniform, albeit, in the flashback it was tattered.

History
When the Kasumioji began manufacturing the Bakkoto, Central 46 denied captain Yamamoto's request to investigate the compound. Nontheless, Shin'etsu offered to sneak in anyway. While there, Gyōkaku Kumoi found and forced a Bakkoto 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. Shusuke finds his dying body and hears his father's last words Beware the Bakkoto.

Synopsis
Shusuke worked with Kumoi for years and gained a Bakkoto 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, Shusuke lets the fire of his Zanpakuto consume him.

Zanpakuto

 * Shikai: His zanpkauto was only seen in a flashback and was his Shikai. It has two curved extensions on either end of the blade, that take the appearance of a hook.