Overman is an alternate version of Superman from a different world in the Multiverse. Unlike other versions of Superman, his primary language is German. This is because on his Earth, the Nazis won the second world war, eventually taking over the planet and spreading German everywhere.
Another Overman first appeared in Grant Morrison's Animal Man #23. He is among several pre-Crisis characters that were returned to reality by the Psycho-Pirate's Medusa Mask. This Overman comes from an Earth based around the "grim n' gritty" stories of the 1980s, the heroes of this universe were actually part of an experiment created by the government. Overman went mad and destructive after contracting an STD. The other inhabitants of this Earth were a black and muscular Wonder Woman, an unnamed Flash, and a punk style Green Lantern. Psycho Pirate pointed out how ridiculous this universe is.