Blade of the Immortal

In Blade of the Immortal, Manji is a talented ronin with a key advantage: except for a rare poison, no injury can kill him. He had previously killed 100 other samurai through criminal means, including the husband of his sister. He was made immortal by an 800-year-old nun named Yaobikuni, and his sister's death forces him to accept the quest that would put an end to his immortality. Manji will be sustained by "sacred bloodworms," extraordinary insects that enable him to survive almost any wound and reattach severed limbs even after hours of separation, until he fulfills his pledge by murdering 1,000 bad men. They function by sacrificing themselves to close the wound; these worms were designed to resemble people as closely as possible without actually being human. They are unable to handle large-scale regrowth, but they may, for instance, reconnect a severed limb or close a hole in the brain.