Elfblood by Kyra Dune

Charlie is an elfblood, descended of a conquered people brought to the brink of extinction in the aftermath of a long war. Being able to pass for human gives Charlie an advantage over most of his kind. Only those who look at his record or those he chooses to tell, need ever know his secret. Growing up in an orphanage is hard enough without having to live with that stigma.

When soldiers come and haul the kids off to a prison work camp, Charlie finds himself no longer able to hide the truth of what he is. If that isn’t bad enough, the magic buried inside him is growing stronger and more out of control. As Charlie struggles with his own problems, and with the dangers of the work camp, he finds himself swept up in a much larger struggle, one whose outcome could decide the future of the world.