I've read far to many drama manga where any character suddenly appearing with hypnosis/brainwashing powers is an immediate red flag for NTR baiting. I doubt this manga will go that route thankfully, because it doesn't have the romance or harem tags (not that missing those tags has stopped some manga before). I'm still not looking forward to seeing this antagonist possibly turn MC's friends and allies against him but it's one of the few ways I can think of that actually poses a challenge to such an overpowered MC.
Brainwashy antagonist aside, I'm interested in seeing how the MC's use of and/or connection to divine energy plays out. Maybe he'll unlock some new power when he figures out he actually can manipulate divine energy or perhaps another antagonist will come along and try weaponise him.