Hagun Seisenki

In 1691 or 1692, Inue Shimbé Masashi and his twin sister Fuse become the new leaders of the Satomi clan after their parents die. Inue also leads the Satomi Hakkenshi, a group of eight warriors loyal to the clan. Fuse believes in the existence of yokai as people, while her brother does not. After being rescued by a yokai named Yatsufusa during a forest outing, she develops feelings for him. By 1991 or 1992, the Hakkenshi have been reborn as students or staff at CLAMP School. Inue is reborn as Kazae Tōma, and Yatsufusa as a math teacher named Shirō Fuyukaze. Kazae is unaware of his past life, and his life is in danger. The reincarnated Hakkenshi must protect him while seeking a way to lift the curse.