There are old sayings of humans: “The value of a man is what he does with power.” And “Power is like a beast; either you tame it or become its food.” -- Anon Guest.
There is a third: Power corrupts. Absolute power corrupts absolutely. All are true simultaneously. Be wary of any Human leader who uses power like a flyswatter, but also of those who dispense their power with tweezers. There is a fourth: It is not how strong you are, but where and how you use that strength that matters.
In some cases, it would have been wise for leaders to know and understand every single one of these sayings. Money is power. Time is money. Imagine if power could be converted into actual hours and minutes of a lifespan. There would be no stopping the wrong kind of leader. Thankfully, the conversion is one way. Time is money. Money is power. There is no way to buy extra time, no matter how hard you try to cheat.
Presented for your approval... the wrong kind of leader... Past or present, it doesn't really matter. There are many, even in the future. Pick an era that suits you. The leader has, through assorted foul deeds, taken his position on an exalted seat. In a prized palace. Wearing the pinnacle of raiments as befit a head of... a city, a state, a nation, a world... take your pick. The blood on his hands is only visible to those who can see souls. The corruption of his heart is no longer visible, since he has arranged for the deaths of all his detractors. He has made it illegal for anyone else to strive for his position. His word is law. His reign is absolute. Nobody can come close enough to harm him and, thanks to a supremacy of weaponry, nobody dare try. Nevertheless...