Yaorochi no Miko-san

Long ago, the King of Monsters led his army in an attempt to wipe out humanity — until a shrine maiden who harbored the evil god Yaorochi tore out his heart and sealed it away. The remaining monsters have attacked the shrine maiden every day since to reclaim their king's heart, but they never stood a chance, and a thousand years have passed while humanity flourished. Now they spend their peaceful days attacking Yuki, the high school girl who has inherited Yaorochi, only to get beaten back every time. A cute shrine maiden and a bunch of silly monsters in an "un"-ordinary daily life! (Source: Kodansha, translated)