[@dragonmancer] Honestly I have to say, while I appreciate the effort, the whole point of making it perfectly clear that dragons are extinct in our universe was to make it so we didn't have any Dragon Slayers.

Your character is pretty much a dragon slayer in practice if not in name. I'm using my rights as GM to say that this character won't be accepted and that you should try and come up with a different concept for him. It's just not going to fit into our roleplay.