If you were to ask Megatron to describe himself in one word, he'd probably go with "heroic". He sees himself as a freedom fighter, leading the Decepticons out of the days of "Autobot tyranny". The fact he's hoping to replace that with Decepticon tyranny isn't really a concern. A fanatic at spark, he revels in every Autobot who suffers at Decepticon hands and doesn't register humans as anything more than "collateral damage."