The representative and No. 1 host of the host club 'Club One.' Despite his youthful face, he is a veteran with over 20 years of experience in the industry. Born on December 17, 1970, he is 44–45 years old at the start of the story (as of 2015). He claims to be 168cm tall (actually 164cm). Blood type AB. He plays the 'younger brother' type host. His real name is Seikichi Handa. He is from the Tohoku region. His host club birthday is celebrated on July 7th. While he looks young, his body and mind are worn out from years of the host lifestyle; he suffers from severe alcoholism and taste disorders. Currently, he only performs 'pillow talk' services once a year for his top client (Ace). He lives in a house with an elderly servant. His family home back in Tohoku is a sake brewery, but after his parents' death, it was taken over by an employee he designated as the successor. His parents are reportedly deceased. Koichi is exhausted and mentally unstable. When he is alone, his expression is dark. He does not discuss his troubles with anyone.