Mugen no Juunin S01

The story of the anime is about a samurai named Manji who has an extraordinary ability, which is that no wound can kill him. In the past, Manji's wrongdoings led to the death of 100 samurais (including Manji's brother-in-law). Yaobikuni, an 800-year-old nun, makes Manji immortal, but later forces him to complete a mission that will ultimately destroy his immortality. Manji makes a vow to compensate for his past wrongdoings by killing 1,000 evil men, and until he completes this task, a type of sacred worms will cause him to remain alive. These worms have an extraordinary ability to heal any wound in the shortest possible time.