[anime] The Boy and the Beast

A martial arts anime by Mamoru Hosoda ("The Girl Who Leapt Through Time," "Wolf Children") is about a boy raised by a man-beast.

9-year-old boy Ren is left without parents, runs away from his guardians, and wanders the streets of Tokyo. There he encounters the great warrior Kumatetsu, a beast-like creature from a parallel world seeking an apprentice. Ren becomes his student, known as Kyuta. Under Kumatetsu's guidance, Kyuta begins training to become a master of martial arts.