I hear in the prequel it explains why he's an asshole.
He ran with a unit of soldiers who were turned into a loose end that had to be tied up. Due to some kind of convoluted loyalty thing he took the fall for offing them. Even though he had nothing much to do with it. This is how he ended up in space.
Since the only men he ever gave a fuck about were dead he decided that should he escape his confinement he would dedicate his life to trolling the entire planet.