He could feel the hand on his face, and that was alright. Then there was the most utterly annoying voice... and then a cry of pain. A cry of pain from Harp that was just loud enough to reach past the sound of the heartbeat echoing through his body. The hairs on the back of his neck stood on end as a much darker side of Bel began to emerge, it was in no way pretty either. 

The demon promptly rips himself away from Harp, eyes swiftly opening. They were still as dark as the void itself, but now blood red irises could faintly be seen against the darkness. The shadows within the stairwell would rapidly be growing darker and darker with each passing second, seeming to eat the light it touched. Slowly black veins would be etching themselves around the demons eyes and down his freckled face as a low snarl erupts from Bel, showing a mouthful of elongated fangs and a forked tongue that had painful looking spikes at each end. The vein's though began to look more like cracks as they grew in number, starting to trail down his neck and past his shirt. Even in a only slightly formed state, he was a bit terrifying. Luckily for them, though, his horns had yet to actually form. It was likely they wouldn't though unless more angels suddenly appeared. 

Without wasting even another moment, Bel pushes off of the concrete slab, launching himself directly towards the imposing angel. Chips of the concrete would break off as he does so from the force of his leap... it would seem he had thrown himself into a form of hunting mode, which sort of made sense, he supposed. He had not been able to hurt Harp, despite how badly he wanted too. And now he couldn't hurt the cupid at all... how lucky was he this angel had come to collect him? Or well, attempt to. Not if he killed and ate her heart first... He had already forgotten that they were in a human building. His hands were bent in an unusual shape as his claws formed rapidly. If no one was going to intervene or try to stop him, this could get rather bloody quite fast. 

Bel was quite fast, even without exerting his full power. And strong too. Possibly even more so now that he knew Harp was behind him, and in possible danger as well.