Harry Potter and the Knights of the Griffon

Lord Voldemort died that fateful Halloween night, but the scars he left on the world remain. Harry, raised by muggles, is thrust into a world of secret duels, esoteric magic and blood politics. Only with the help of his friends, both old and new, does he have a chance of surviving it. And what's this about the crown of Arthur? Extreme canon divergence, AU. Rated M to be safe.