There was a story there, but between the poor guy having to deal with Eliot, and Manes, he wasn't about to bring it up right now.
"Oh, you know. Came from a world that isn't much better than this. Get close with a few people. A few of them die, one of which was basically my best friend here, so I start shoving people away and being a loner." It was easier to survive that way. If you didn't have anyone to lose, you didn't have to be as careful.
"Right now, I just run supplies between different camps, help out Magnus when I can since the poor guy can't leave the hideout, and do my best to stay alive."