I was reading a manga called Berserk (WARNING: NOT WORK SAFE, NOT FOR THE FAINT OF HEART, LOTR-LEVEL LENGTH), and I noticed something peculiar - Gatts, the protagonist, is inordinately powerful. Not only does he have a robot arm that conceals a cannon, he has a monstrously large sword (no Freudian imagery intended) and can wield it with ease. Also, he's a jerk of the first order, gladly sacrificing those who help him, and pushing away those who try to get near him. Gatts is scum. But for some reason, I can't stop reading about him.
I actually watched the much-softer Berserk anime before the manga, so perhaps that colored my perception of Gatts. He's a vaguely Byronic figure, an arrogant outcast from society on a single-minded quest to wipe out the demonic cult, the God Hand. He abandoned his girlfriend after she went insane, and kills people without a second thought. However, there is something strangely mesmeric about Gatt's one-man crusade. Part of it is the production values of the manga itself - the artwork is top-notch. Unusual for a manga, the anatomy of the character's is very detailed, and the art remains consistent from panel to panel. There's nothing to shock the reader out of the story.
More than that, however, I really want to find out what happens.
So why is it? How was Berserk able to make such a monster into a sympathetic protagonist? I've noticed this is Quintin Tarantino's Pulp Fiction; Jules and Vincent were ruthless hitmen, and yet I watched a two-hour movie about them anyway. Maybe it was because both Gatts and Jules believed in something greater than themselves, and fought for it. However, Gatts doesn't have any readily apparent objective, besides Kill the God Hand. He literally has nothing to live for, except his all-consuming quest for vengeance. People have ranted and raved about characters like this don't work, so... why does it work in Berserk?