Hero is isekaied into an RPG world where he has to face a demon lord. His reward is said to be a princess. However, it's not much of a reward as she is very visually stunning but exceptionally himedere and tsun-tsun in nature. Even worse, she's carrying on an affair with the captain of the guards and has no interest whatsoever with the hero. About the only thing that is somewhat redeeming about things is that the hero, through the use of his skill board makes her life just as uncomfortable as his is, usually by making her horny at the worst times.