Crowley didn't have the faintest idea what blood type John was, although if things continued like they had around the Manor he should probably find out. Still, it didn't matter. He was aware enough to remember that O-negative was the universal donor and could be given to anyone of any blood type. He produced two bags of it on Raphael's tray, not moving from his spot in the doorway or speaking. Instead, he just watched Adam pull the requested pills from the cabinet.