Well, if he's a secret, then how do you know that? Or are you saying that the rest of us are all illigitimate bastards from all of Santa's flings while you actually descend from his wife? XD
Hell hath no fury like a woman scorned because only women can give two tits for every tat. ♥
Of course he's a ninja! How else do you explain the fact that nobody's ever seen him? At least none who lived. That coat of his didn't get red from spilling juice on it, that's for sure.
I'm voting cat girl, but only because I rather like the idea of a christmassy neko sneaking in to leave bells and trinkets for all the kids. Plus there's the matter of all that milk.