Demon Prince Zenki

Enno Ozuno, Master of the Enno temple used the demon guardian spirit Zenki to defeat the demon goddess Karuma. After defeating Karuma, he later sealed Zenki away in a pillar until needed again.

Centuries later, his descendant, a school girl named Chiaki Enno (役 小明, Enno Chiaki, or Cherry Night) is able to free Zenki, although the demon currently has the form of a brattish demon child. To transform this extremely defiant demon into the form that made him useful by her ancestor, she uses a bracelet that appeared on her wrist when servants of Karuma broke the seal that imprisoned a seed of Karuma. Zenki appears because the seeds of Karuma (which look like eyeballs) start appearing and turning people into monsters and Zenki is needed again to eradicate this menace.