Use by the Nazis

"Der Übermensch", a German propaganda poster from 1942.

The term Übermensch was used frequently by Hitler and the Nazi regime to describe their idea of a biologically superior Aryan or Germanic master race; a racial version of Nietzsche's Übermensch became a philosophical foundation for Nazi ideas.

The Nazi notion of the master race also spawned the idea of "inferior humans" (Untermenschen) who should be dominated and enslaved; this term does not originate with Nietzsche, who was critical of both antisemitism and German nationalism.

https://en.wikipedia.org/wiki/%C3%9Cbermensch