The lyrics of the song are pulled from chapters of Thus Spoke Zarathustra: A Book for All and None, a novel by German philosopher, Friedrich Nietzsche, inventor of the Übermensch.
The concept of the Übermensch coincides with the ideology of the Nazi's in the series, and is mentioned by Stroheim when revealing his gatling gun in Episode 19. Even though Nietzsche himself was a fierce opponent of what later became the ideology of the Nazi party, some of them were moved by his work without being "converted" (or used the severely manipulative version of his work published by his sister), as it was probably the case of Stroheim.
The given English translation of the lyrics here are taken from Thomas Common's translation of said book.
