Baoh the Visitor

Ikuroo, a young man, has a parasite called Baoh implanted in his brain by the organization Doress, granting him near-immortality. The Baoh parasite allows him to transform into a powerful beast in times of danger. Sumire, a young girl with psychic abilities, helps Ikuroo escape from Doress when they're transporting him on a train. Dr. Kasuminome, the scientist behind the Baoh project, is determined to recapture Ikuroo using his resources and superpowered agents.