Ring of Supremacy

Long ago, twelve rings were made by the heavenly order of gods. The rings were entrusted to the human race. This caused uproar among the demon clans throughout lilara(their planet). The demon god forged one ring called the Ring of Supremacy. The Ring of Supremacy was said to be stronger than the twelve rings of power combined.

This story starts out with a guy(Percy) and his friend(Emilia). After Emilia finds the ring of control she and Percy leaves the academy for their own safety.