Devilman Episode 1: Revival of the Devil Clan!
Episode 1 of 39 of Devilman, aired July 8, 1972, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Lord Demon orders three demons to fight to the death. The winner will choose a human, Akira Fuodo, and assume his identity while trying to bring pain and suffering on the Earth.