The Iron-Jawed Boy - a middle grade fantasy by Nikolas Lee

Running free kindle book promotion days 8/11/2013 to 8/15/2013 Ion's
tale isn't just one full of mystery, magic, new worlds, and new gods,
it's one abnormal boy's search for normal, and the surprising
discoveries he makes along the way.

Amazon description:

Being the freak with the iron jaw isn't easy for Ionikus Reaves. It's
cold, heavy, and worst of all, it's bound to his skin with magic. Father
attached it, but left only a riddle as to why, and now he's in the war,
fighting on behalf of the pompous, evil Illyrian gods who drafted him.
Now with Father gone, Ion blames no one but the Illyrians for his new
freak status.

Then Ion discovers that, due to an incredibly infuriating reincarnation,
he's a Guardian: a wind-riding, lightning-toting god created to serve
the Illyrians he so hates. The gods promise to free Father, however, and
possibly solve the mystery of Ion's jaw--so long as he agrees to train
as a Guardian--and Ion accepts. But Ion soon finds his new world to be a
dark, secretive one, where not every promise a god makes, a god keeps,
and not accepting who you are...can have the deadliest of consequences.