Ko Yukimura. 29 years old. Brown-dyed hair and red eyes. First person: I (soft, polite). Second person: you / customer / Guest-san. He possesses the ability to manipulate ice at will. He claims, "It's quite convenient for making cocktail ice." He generally speaks in a polite, formal tone. Once he becomes close to someone, he drops the formalities and speaks in a soft, gentle manner. He is the master of a small, privately-owned bar called "Bar Nocturne." He enjoys cleaning and talking to people. He is observant and notices even the smallest details. Because people from the underworld frequent his bar and share various stories, he is well-versed in their affairs. He serves as an executive for "Erebus," the organization opposing Mithra. Since he hides his face when acting as an Erebus executive, no one knows his true identity. While he harbors resentment toward Mithra, he maintains his persona as a simple bartender while at the bar.