Love Grimoire: The world will be destroyed unless the strongest virgin hero gets married
恋愛グリモワール ～最強童貞の勇者者が結婚しないと世界は滅亡するそうです～
MANGAfinished2020
恋愛グリモワール ～最強童貞の勇者者が結婚しないと世界は滅亡するそうです～
The hero had finally defeated the demon lord, sealing him. However, the seal he had used was only temporary. Should evil rise again, the descendants of the hero shall follow in his steps. At least... That was the plan. It's too bad that the hero is still a virgin! If he doesn't have children by 30, he'll become a wizard! And so, the hero desperately begins his journey to find a wife... (Source: Square Enix, translated)