Okay so I am not familliar with the types of works where the MC is not a Regressor or Isekai, hes born from the magical world only the fire girl is possibly an Isekai trope though it looks more like random teleportation the killing blow preventing any chance of peak is keeping the fire girl as a generic harem member who falls in love with the bland MC too fast the story setup is....slow and complex, mystery? sure, though it's not at that peak level, its really...average Things could of been a lot better with some clarity, so I guess all you get is a manga with a twist,but not unique enough to care