DJ.Coo, whose real identity is Rei Kurokawa, works as the resident DJ at the fashion store Prism Stone. He has tan skin, striking white hair, and green eyes. His distinctive style consistently includes a gray hat, sunglasses, a red coat over a black shirt, silver rings, a long gray skirt layered over black pants, and shoes. His speech is characterized by randomly inserting English words and frequently punctuating sentences with "Cool."

He engineered an android body for Momo, a messenger from the Prism World, allowing her to live in human society as Chisato Ibara. DJ.Coo actively contributes to Prism Stone's operations, aiding in staff recruitment and supporting the store's various activities.

Four to five years before the main story, he was a top Prism Star named Rei Kurokawa, rivaling Jin Norizuki and Hijiri Himuro. During the decisive Prism King Cup, he forfeited immediately upon learning of Hijiri's injury, effectively handing the title to Jin. This event led him to abandon his Prism Star career. He adopted the DJ.Coo persona, using sunglasses and a cap to conceal his identity, and became known as "The Legendary Father of the Street Movement" for his profound influence on street-style dance culture. His legacy inspired Kazuki Nishina to dye his hair white in homage.

His character development saw his role as a former Prism Star solidified later, drawing on the concept that he would appear handsome without his disguise. Throughout the series, DJ.Coo assists the main characters, facilitating Rinne's integration into the human world and supporting Naru Ayase in her management role at Prism Stone, always acting to enable others' goals rather than seeking personal acclaim.