After a swordfight, Amane, a young samurai with a haunted past, is left for dead--only to be saved by a mysterious tattooist who imbues Amane with the immortal spirit of an oni demon. From that day on, Amane ages no more. Amane learns of another with a similar oni --one that requires its host to kill--which leads Amane to the realization that the "other" is the man who murdered his sister years ago. But when his decades-long quest for the murderer...