"Then why are you sittin' here cryin'?" He wondered whether Aleister even realised. Must be a foreign feeling for him by now, those wet trails down his cheeks. "Why is this the most you've cared?"

Obviously, because he was human. And because emotions were strong. Emotions were so much stronger than those creatures could realise. "I've got a deal for you, darlin'. A vial of blood. Not just any blood. I'll bleed myself in front of you, just so you know you're gettin' the good stuff. And in exchange you're takin' me to the other half of the angel tablet. The one you've hidden."