In other worlds, this would be a good thing, but the problem is, this is a totally messed-up world.
The NPCs players like will be killed — or corrupted, fallen. If players discover it early, maybe they can solve it. But if they discover it late, then they'll watch helplessly as the other party falls, transforms into a Demon, and have to choose whether to kill her or be killed by her.
Or during a battle, their harem is killed by the enemy... NPCs rarely resurrect after dying unless it's a Soul Card. Moreover, after they're killed, their souls are taken into the Evil God's Subspace, permanently becoming its playthings.
And more cruelly, players will still see them in the Evil God's realm.
