The monster in the 1st layer

Zatiel wasn't surprised about this man knowing his true identity. Actually, if he had not figured it out with all the information he had, the Neo-Demon would have found it odd. 

"Why do you speak as if this was the first time you see me? Didn't we meet a long time ago, when I defeated you and extracted your soul from your body?." Zatiel was speaking peacefully, and his attitude appeared to be extremely relaxed, but the truth was he had his guard up and attempted to discern the authentic nature of the man in front of him.

The Final Purgatory was strong enough to contain this man and stop him from using his power. The reason why he could form an incarnation of energy was due to Zatiel allowing him to do so. Therefore, the damage he could do physically was almost null, but just like the Ancestor of the Neo-Demon race could trick a unique entity like the Sage with just his words, the blonde man was also capable of such a feat