"Once we finish this, we should go sightseeing together."
Normally that would be a death flag, but the MC has the power of plot armor to save him from such things.
Captain Annie, I guess. Yet another to the growing harem.
The surprise here for me is him meeting his betrayer this early. But I'd be surprised if he'd kill him. At this point the MC is practically fantasy Batman with magic powers (in lieu of fancy gadgets) ruling as a demon king. He's not personally wealthy, but as the demon king he does have the demon world's treasury at his disposal.
Human? ✔
Mask to hide true identity? ✔
Fights evildoers? ✔
No killing rule? ✔
Backstory with dead family members? ✔