Nani mo Shiranai Sai Kowa Maou, to Ai Yuusha ni Torawareru

The most fearsome demon king, who is basically a blank slate, is captured by the hero who loves her dearly. She was kissed, her breasts and private parts were exposed, and she couldn't resist the pleasure for the first time... The Demon King, who had previously reigned with overwhelming power, is now dominated by the Hero. "I'm not going to kill you. You're mine." What is the hero's real objective?