Wimpy Demon King and Tsundere Hero

From EPS: In order to defeat the Demon King of Mano who was feared by the people, prince Ike embarked towards the castle alone. But, he was easily defeated by the retainers. However, in order to defeat the Demon King and make a name for himself, Ike spends his days attacking the weak Demon King, who keeps running away. On the contrary, he gets to know the Demon King who worries about him(Ike) and treasures plants. And before he knew it, he started to enjoy being with the Demon King…?!