To be fair, if karma does exist, he'll probably won't notice it until he starts his next life. Odds are he'll be reincarnated as some kind of bacteria you find in dog turds, or something.
That said, I like Alvin.
He seems like unapologetic traitor, but he doesn't actually want to see the people he likes get hurt. He's indecisive and screws up again and again, but he helps the others just as much if not more. And when he finally figures out he can't and shouldn't continue living the way he does, he tries to make amends.
(So, yeah, basically he's a badboy who needs a hug and I guess I just can't resist those charms <_<)
As for the other characters, what bothers me is that much of their development is so easy to miss out on since it's not part of the main quest. It feels like bad storytelling at times. Of course, that all ties in with the game being rushed out to meet the deadline. If it hadn't been the anniversary game, it might have had much more content.