I was summoned to another world with the power of magical wish contracts
My name is John Smith and I was summoned to another world yada yada human kingdom alliance yada yada demon king yada yada you get the general idea. It turns out I have an extremely broken power as I am able to put an end to the war between humans and demons, well not necessarily as the cost is too great for that. What cost? Well I can grant any wish possible but the wisher needs to pay a price to me that I keep for myself. Now to an extent I can choose what the price is, as I need to think it a fair price and one I want myself. The thing is, if I save someone else's life I think it is only fair that their life belongs to me now. You can see the problem when this is on a world scale. I can not stop the war but I can take the top demons out of the picture, the price is still great but at least if the human alliance shares the price it can be granted. What is the price? Well I am a young healthy teenage boy, the price was well... every cute noble girl. It turns out in the whole alliance there was 1278 cute noble girls. Well there was a bit extra for that price but this was really the main bulk of the price. The other part was money and land, 25% of land and money from each nation part of the alliance. This is how my life started in this other world, wiping out all the top-level demons, getting a harem of girls and starting my own kingdom with a bunch of money too. The war with the demons would only last a few more months before the demons spread across the world scattered and peace fell upon the world. I go on adventures, grant people wishes and lived peacefully. Or so I thought 10 years later all the top-level demons returned, this is why you should be specific when you make a wish. Sigh.