Fire Wolf

Don't recommend reading if you have not read Lost Hero series

Leo had always been the seventh wheel but one night he was bitten by something and it was slowly changing him into something he never known. He could suddenly do things inhumanly possible even impossible for a demigod. His fate is tested when he is given a prophecy to lead a quest and slay the one who has bitten him within the spand of a month. And if he doesn't make it in time he will be stuck as a monster forever.