Be careful for those who are looking for fanservice because the women in this manga are full of maid whore waiting for someone to buy them, don't believe about a personal virgin maid the plot said, they fck all other heroes in the background, they are almost like street prostitutes, the system itself is actually full of ntr stuff although the plot says otherwise if you think about it carefully, for those of you who had a crush on your girl classmate's in the past, this bullshit might hurt, because the female classmate who was also summoned was practically used as a full-time baby factory slave for all the infertile Isekai men by turn, ah and also the fighting scene is below average to be honest.

Well... The world they are is 99% a wasteland and only 1 country exists within a barrier to protect them from the outside. In the country are "Dungeons" which provide everything they need. But they require strong people to enter. It doesn't help that most men in that world are infertile and they need to summon people from other worlds to increase the population and have the summoned men impregnate lots of girls.... Thats all good in the men side, but summoned women have their personality removed/sealed and used as babies factories as women from other worlds are "compatible" with the % of men who are not infertile. I hope mc can fix that issue buts its unlikely.
The story goes how a low-ranked hero (MC) enters the dungeon and actually is a extremely strong fighter. He gathers eventually is stronger than high ranked heroes by a huge amount and gather girls that he likes.