Pol Pot
Mao Zedong
Ghengis Khan
Kim Jong Il (Kim Il Sung was no picnic but he cared for his country like Hitler)
Idi Amin
Mugabee ( former ruler of Zimbabwe)
Vlad the Impaler (haha) He killed roughly 25% of the population at the time
Uday Hussein
This would be alot easier if it were more modern.
Murder was very commonplace hundreds of years ago
Some will say Hitler, Stalin, Saddam,
Those 3 in particular basically just ruled their countries with iron fist. If it wasn't Hitler, it would have been widepsread Communism. At that time, no one liked the Jews.
As for Saddam, look what the Middle East has been like Post Saddam. There would be no Isis if Saddam were in power. He was a bully to the Middle East and kept them in line. He was no threat to the USA. He was too smart for that.