He ordered the deaths of millions, and his actions caused the deaths of millions more. Yet, Joseph Stalin and Mao Zedong, in that order, killed many more people than Adolf Hitler could be attributed to. The top three murderous dictators were Mao, Stalin, and then Hitler. Hitler was the only one that ordered deaths mostly based around ethnic exterminations (Ethnic cleansing), however, which makes his murders ethically worse. Hitler was the worst person ever.