Kyuuji Natsume is a childhood friend of Agetarō Katsumata and the third-generation owner of Tōyoko Neon Denki, a family business that specializes in neon signs and electrical contracting. He holds a special qualification in electrical engineering, which he puts to practical use throughout the story. As one of Agetarō’s close circle of four friends who are all third-generation proprietors of local Shibuya businesses—collectively known as the third-generation brothers—Kyuuji is a reliable and straightforward young man. He is often called upon to assist with the technical side of Agetarō’s DJ aspirations, wiring up DJ equipment in Agetarō’s room and erecting neon signs to draw crowds to early events. His personality is practical and supportive; he does not seek the spotlight but is always ready to lend his skills when his friend needs help. Over the course of the story, Kyuuji and the other three friends become increasingly captivated by club culture. They begin training in dance in earnest, eventually evolving into Agetarō’s dedicated dancers, performing as part of his crew. This development shows Kyuuji stepping out of a purely behind-the-scenes role and growing more comfortable on the floor. His motivation is rooted in loyalty to Agetarō and a genuine enjoyment of the vibrant club atmosphere. He does not have a personal conflict of his own but serves as a steady, capable anchor in Agetarō’s support system. His notable abilities include his electrical expertise, his growing dance skills, and his calm, dependable presence among the group. His key relationships are with Agetarō, his three fellow third-generation friends, and the wider community of DJs and clubgoers that forms around them.