I really don't know either. I mean you're basically a mix between the historical Dark (Black) Knight and Batman. Totes making an Au Ra to play Dark Knight.

I think it's because the scenario universally portrays the PC as an upstanding, righteous hero, and playing a Dark Knight won't deviate from that. People want a PC that isn't the "righteous hero" type, but due to the fact the devs can't develop a more "neutral" or "evil" campaign, every class has to be unambiguously heroic. Or something like that.