Ryūjin Kofune, a secondary figure linked to Café Vinyl, operates as both the establishment’s owner and the enigmatic "Café Master" portrayed in the anime. He shares duties with Amano Airi at the coffee shop, maintaining a steady presence behind its scenes. His past ties him to the storied DJ collective L.M.O., though the exact nature of his involvement remains shrouded in mystery. Within *D4DJ Groovy Mix*, he transitions into a guiding role as the navigator for the "DJ Road" mode, offering players tactical insights during gameplay. Beyond these functions, his personal history, potential character evolution, and interactions with central figures or external narratives remain unexplored across official media extensions.