Maou no Musume wa Yuusha to Seiryaku Kekkon shitai

The war between Idal, the country of demon race, and toile Kingdom, the country of the human races, have been going on for a long time until an overtue toward peace was offered by the demon lord. Following this, the demonic princess, Lieselotte, was married to the Hero, Schmerz and she'll live in the human world as a hostage of short. But this is just Lieselotte's first step toward her ambition, and her future is full of hardship that she must overcome...