Devilman (1972)

Akira and his father are killed while mountain climbing in the Himalayas, and Devilman chooses Akira's body as a cover to disguise himself. When Devilman/Akira moves in with the Makimuras, he falls in love with Miki and is distracted from his mission cause to death and destruction on Earth and to pave the way for a demonic invasion of the human world. When the lord of the demons sends a succession of demons to eliminate Miki, Devilman/Akira fights to protect her.