Devilman

Akira Fudo, a teenager who had been climbing with his father in the Himalayas, suffered a fatal accident. His body was found and taken over by Devilman, a demon soldier seeking to pave the way for a demonic invasion. Before his mission could proceed, Devilman encountered Miki Makimura, a childhood friend of Akira's, and became infatuated with her. This led to a change in Devilman's behavior, as he resolved to protect Miki and humanity from other demons, including his own kind.