[@CrystalApple] Gods, recent history kind of people, (Stalin, Gandhi, etc.), and like way out their fantasy books such as Harry Potter. I'm leaving it pretty open as I really like having unique characters with deep lore surrounding their legend.

Van Helsing
Joan of Arc
Vlad the impaler 

Terrible people are fine, I expect some of the characters not to like each other but you have pretty much free reign as to the history you pull from.