Attila the Hun is the answer to this question. He is known to be the 5th-century king of the Hunnic Empire but in order to get there, he had to kill his brother first. He was truly a king to his people but he is also ruthless and is also known to be quite barbaric. He was able to invade the Roman Empire through his cruel and barbaric ways.
His death is actually quite different from what other people may probably expect. He died when he suddenly suffered from a nosebleed in the middle of the fight. Upon trying to calm it down, he choked to death. His death was cheered and celebrated as he is known to be “The Scourge of God.”