Corpse Princess Series by Yoshiichi Akahito

Fight corpses with corpses!!Reanimated corpses called Shikabane walk the earth, but the Kougon Sect of the Grand Marshal School of Shingon Esoteric Buddhism has a means to combat them. Enter the Corpse Princesses! Undead-killers (usually young women) stand as humanity's first line of defense against the evil that lurks in the shadows, but can humanity tolerate defenders who are corpses themselves...?One Corpse Princess, Makina, may be the first to find out!

"I'm recruiting shikabane in order to crush the Kougon Sect." So says the former chief Gonshou-soujou of the Kougen Sect -- Akasha Shishidou -- a name to be feared and loathed. And like it or not, encountering him means nothing but death. As events begin to unfold, others are mercilessly caught up in his game. Even the girl who embodies death is no exception.Shikabane kills needed for Corpse Princess Makina Hoshimura to ascend to heaven: 96.

"I'll destroy you all...! Every last one of you," vows Makina Hoshimura. She and Ouri are brought together by pity, dread, compassion...and a promise. This transient world of ours is driven by such passion. They know they can't bring him back, yet they plunge deeper into the otherworldly mire brought about by the Unclean Bunch.Shikabane kills needed for Corpse Princess Makina Hoshimura to ascend to heaven: 95.