Blade of the Immortal(1999)
A novel by Hiroaki Samura
Manji, the immortal samurai, is condemned to a life of combat until he slays a thousand evil men. He works as bodyguard for Rin, a young woman who seeks to avenge her father`s murder at the hands of the deadly Kagehisa Anotsu. But even with Manji`s instruction, will Rin ever be able to stand against such a powerful and ruthless adversary? And in her consuming quest for vengeance, does she risk becoming like him?
Used availability for Hiroaki Samura's Blade of the Immortal