I probably should have just done it in the very beginning. I know that you humans are stubborn and will keep your mouths clothes until your dying breath, so long as you remain loyal.

[ He knows perfectly from experience. Stubborn loyalty that kept him wrapped up in the crusades affairs even after he had stopped going to the church and left the army all together. Because when they said that they needed him he couldn't look at the remaining of his comrades in the eye and say no. ]

I won't be able to determine what you are exactly, but I'll least know that you're not completely human once I've taken a little bit out of you. [ Thankfully Gran has done a majority of the work for him by tipping his head, which leaves Crowley only needing to crouch down to his height. ] But if you struggle then I'll just drink every last ounce of blood you have in you.