I think Caim from Drakengard is a strong contender. He's an unhinged sociopath whose only outlets for expression are killing people and screaming battle cries, and after he's rendered mute ten minutes in he can't do the latter. To make up for this he gets to ride around a dragon and perform the former with incredible eficiency. Men, children, humans, monsters, there's no-one Caim won't chop into bits with a sword or burn to a crisp with his dragon. And given that the enemies he's fighting are a empire entirely composed of crazy nut-jobs worshipping the local cosmic horror, there's no shortage of dudes for Caim to butcher. And then, depending on what ending you prefer, he either drops the hero front entirely and starts killing dudes indiscriminately in the sequel, or flies his dragon into Tokyo and indirectly causes the apocalypse. What a great guy!