Identifying the "most cruel/evil person" in all of history is a subjective and contentious topic. History has seen numerous individuals responsible for heinous acts and atrocities, and comparing them on a scale of cruelty is difficult.
Some individuals who are often mentioned for their brutal actions include:
Adolf Hitler: The leader of Nazi Germany during World War II, responsible for the Holocaust and the genocide of approximately six million Jews, as well as millions of other victims, including Romani people, disabled individuals, and others deemed undesirable by the regime.
Joseph Stalin: The leader of the Soviet Union, known for his oppressive rule, forced labor camps, and purges that led to the deaths of millions of his own people.
Pol Pot: The leader of the Khmer Rouge in Cambodia, responsible for the Cambodian genocide, during which nearly two million people died due to forced labor, executions, and starvation.
Genghis Khan: The founder of the Mongol Empire, known for his ruthless military conquests, which led to the deaths of millions of people across Asia and Europe.
Idi Amin: The dictator of Uganda in the 1970s, responsible for numerous human rights abuses, extrajudicial killings, and the persecution of ethnic and political groups.
It's important to note that there have been many other individuals throughout history who have committed terrible acts and atrocities. Additionally, historical context and cultural perspectives can also influence how certain figures are perceived. As such, it's challenging to definitively single out one person as the "most cruel/evil" throughout history.