Rein activated his Furnace body with all his might when he was sure that the demons had shown all their cards. Immediately got a huge boost in power and the tides of the battle changed. The other human true gods were still in quite some trouble and the sect master of Divine Scale Pavillion was still injured but Rein started to push the demons back. That in turn made other demons to focus on him which lessened the pressure on the other true gods.
This turn of events made Alcusus mad. The sudden boost in Rein's strength was completely out of his expectations. He was sure about dominating Rein in battle even if he could not do that very quickly. But now it was him who was actually getting dominated. This made Alcusus' mind go blank for a moment.