Now get this: What if “Overlord,” but everyone is basic? We’ll also ditch the MMO backstory with the MC having his roots in player driven history and culture for some single player post-game rts where MC customized a bunch of female NPCs. Plus a few de-monstered Nazerick knock-offs for gender equality. And we can dump the perspective jumping in Overlord to just follow MC as he discovers the thrillingly original manga plot of “humans liars, non-humans cool.”
All that said, this might end up okay. Get some intrigue outside that abandoned plain MC’s castle found itself in, and maybe trade some of Overlord’s monster-edge for more grounded medieval anime/fantasy, and maybe it will become something decent. But so far this looks like Overlord after trading in the unique bits for basic dweeby gamer wish fulfillment.