Mizushika Denai Jingu [Cop] wo Sazukatta Boku wa, Fumou no Ryouchi de Suki ni Ikiru koto ni Shimashita

Sian was born into a family of wealthy aristocrats, suggesting a life of ease and luxury. However, during his coming-of-age ceremony, which grants magical abilities to the celebrant, he receives a seemingly worthless "cup" that only produces water. As a result, he is deemed useless and ostracized to live as a nominal feudal lord in the remote desert region. Despite hitting rock bottom, Sian is undeterred and sets out to revive the barren area. Using his "cup," he restores the dried-up oasis and brings happiness back to the locals. Eventually, his "cup" is revealed to be the Holy Grail, further fueling Sian's determination. With his newfound power, Sian challenges himself by creating regional specialties to sell, cultivating enchanted plants, and constructing his dream city.