Hitler is commonly used as an insulting comparison for people being too authoritative or asshole-ish. Saying “don’t be a Hitler” or “calm down Hitler” are common enough to where he is regarded as one of if the not the worst person in history. Who took this mantle before him? Are there any historical examples of a separate person being used before Hitler took their place?
More of course can be said, but this answer should be of interest for you.