Baoh the Visitor

Ikuroo, a young man, has a parasite called Baoh implanted in his brain by the organization Doress. This parasite grants him near-immortality and the ability to transform into a powerful beast. Doress plans to exploit Baoh's abilities for their own gain, but Ikuroo's escape is facilitated by Sumire, a young girl with psychokinetic abilities who's being held captive by the organization.