Tomoe, Gozen

巴御前

Saisei is a zombie who fights for Saishi. She wields a naginata in combat.
In the manga, Akira killed Saisei after neutralizing her ability to warp damage to her opponent. He respected her, however, because she fought so hard to protect Shinrei, whom she secretly loved.
In the anime, she fought alongside Benitora and Migeira at the gates of Mibu Castle. She "devoured" Yuya by absorbing her into her endless space body, but was ultimately defeated by Yuya from within.