So an angel. [ Which would make Portland hilarious if Childermass had any idea what Zangetsu had ended up being. ] Or something akin to it.

[ He can't even add 'but scary' since angels are typically described as scary anyway. ]

In any case, if it does come down to that, if he does die, I would make it your job to ensure he returns to the carnival. The egg itself is meant to activate on its own, I think, but he'd have no defense out in the library...