Blade of the Immortal

Manji is a samurai on the run after following his superior's order to kill a corrupt lord and his followers. Manji chose to care for his now insane sister Machi. While on the run, Machi is found being held hostage by a large group of rōnin out for a bounty on Manji's head. When Manji does comply with the rōnins' demands, they proceed to kill Machi. In retaliation Manji kills every member of the group, but is mortally wounded. As there was nothing left to live for, he accepts his death, but Yaobikuni implants "sacred bloodworms" into his body, which heal him.