Oooooooooookaaaaaay.......
So let's analyse this:
The dark god descents on that world and...
He meets the princess and suddenly he is her favorite friend. The king is on his side after meeting with him. A Harem develops naturally around him. He gets his own private army with loyal troops. In the territory of an enemy nation of his "friends", monsters suddenly appear and their government is wiped out around the time he arrives. Only his own troops or allied troops can efficiently destroy those monsters. (Don't forget, that he can create stuff.) The leader of an rebellion army switches sides after been taken in custody of his squad. Another leader of an enemy nation, hellbent on conquest, suddenly gets all chummy after meeting him, their wise women gets all cozy with him too and after he visited their capital that nation suddenly changes politics and is all too happy to strife for a peaceful co-existence. It becomes known, that enemy spies suddenly turned coat after meeting him. The princess, who has been announced to be married to some other noble, suddenly doesn't have to after he arrive back at that capital, because instead she all of a sudden will become Queen herself and the place of the king is kept free ... maybe for a certain someone. The opposition leader of that country also turns down his resistance after a meeting with him. AND EVERY LEADER OF THE KNOWN WORLD JOINS PEACEFULLY IN A PLAN HE HAD HIS FINGERS IN!!!!!!
It's a kind of magic... If I would just be a bystander and that's the info I get (dude with cheat powers arrives and all that happens), well ... I'd never agree to a meeting with him. Not even once.