Corey serves the Zoble Empire as one of the demons resurrected to threaten humanity, operating under leaders like Demon King Over-M (Obami) alongside fellow demons Piscalat, Nickel, and Neput. As a demon, Corey clashes with the Idaten deities. During a battle against the Idaten warrior Hayato, Corey struggles and is defeated. This defeat leads to capture by the Idaten. Ysley, an Idaten strategist, then performs neurosurgery on Corey, Piscalat, and Neput, brainwashing them into switching allegiance and fighting against their former demon comrades.

Corey's brainwashing is later reversed by Obami, restoring original loyalties. Upon regaining autonomy, Corey harbors significant hostility specifically toward Ysley due to the endured psychological and physical manipulation. This anger is not extended uniformly to all Idaten; notably, Corey exhibits no comparable animosity toward another Idaten, Paula. When subjected to torture or intense suffering, Corey explicitly vocalizes the pain being inflicted, demonstrating a capacity for distress and self-preservation.

Corey possesses a childlike appearance, resembling a child soldier. This visual design contrasts with the character's role in violent confrontations and the narrative's exploration of demonic forces.