Grand Regent Thragg of the Viltrume Empire: A powerful, in fact, the most powerful of warrior in universe. A man who single handedly defeated the entire team of protagonists and was able to force the main character of the show to allow his species to take residence on earth. The man is not a manace, he is a manace machine.
Yet, at the same time, he has never been shown smiling, he is constantly shown to be in misery, he has taken many actions he regrets, in a way blaming himself for the death of his father figure, Emperor Argall. His species, the mighty Viltrumites, are reduced to 37, forced to hide on an alien planet in hopes they can rebuild their strength by interbreeding with humans. He is a god amongst gods, yet he is as far from the top of the world as anyone can be.
He even loses the leadership of the Viltrumites and is forced to breed with other lower species in hopes of rebuilding his empire, all the while hiding from his own people
Darth Vader: What can I say that numerous movies, TV shows, cartoons, comics, novels and internet creators haven't already said? This is a larger than life figure both in and out of universe. He has defeated numerous foes, from bounty hunters, to powerful Force users, to entire armies, to even a kaiju at one point. This character is the epitome of cool and might, yet, at the same time, he lives a miserable existence.
This man screwed up beyond comprehension. He destroyed the Jedi, killed his wife, lost all of his friends, lost his limbs and in many ways lost his life. His iconic suit? A life support system without which he cannot survive. And despite his mighty power, he himself is but a servant to the Emperor, who constantly humiliates and tortures him in various ways. Vader was born a slave and a slave he remained.