Role Reversal/ The Fading Light

[Bored Fiend]

I am using a novel assistant but I need a real person to bounce ideas off of, right now the only thing I have to go on is i'm wanting to do an Isekai power trip type of thing, where a guy living a fairly basic life, a cog in the machine - simple and easy, a life without any real meaning or the like - gets summoned by a demon King/Queen to fight against the evil plighting the world, zealous humans using a gods name (preferably against the god's will) to slaughter anything with even a slight difference, though the mc more or less just takes everything the world will provide, not really focusing on the humans, until the humans invade the kingdom he was summoned to
After the attack anything can happen, whether his "pets"/ harem get murdered and cause him to go even further into the depths of his mental illnesses, or the people he had come to know and cherish get enslaved and he has to free them
I dunno, I am just a bored fiend after all