Basic Trope: A character voluntarily takes all blame to save others, and no one else knows it.
Straight: A noble Anti-Hero discovers a cosmic threat to the mankind, becomes a vicious God Emperor to prepare the world for it, and is finally killed by La Résistance, knowing that they are now strong enough to fight back whatever he foresaw. They just think they've deposed a brutal tyrant.
Exaggerated: The Big Bad ruthlessly pursues and exterminates anyone who suspects there's good in him, just to maintain the impression that he is a monster.
La Résistance realize that the evil emperor they've just killed must have been trying to protect them from whatever and resurrect him. It turns out, he has never given a shit about them and proceeds to Take Over the World again...
The Big Bad skillfully fakes his own death, living to an old age in peace, enjoying the world that he saved.
Double Subverted: The resurrected Big Bad only takes over the world again in order to complete his real plan of saving humanity that was interrupted by the resistance earlier. He then dies once more.
Parodied: A Wide-Eyed Idealist with a wrong idea about his fellow humans' intelligence attempts repeatedly to pass off as a great villain and get himself killed for a noble goal. They just laugh it off.
Zig Zagged: The Big Bad is an eternally reincarnating scheming deity whose goals are so confusing, everybody and their mother have different opinions on whether he is really saving humanity or just having his villainous fun.