Kobayashi operates the BB Lounge nightclub in Shibuya. He possesses a strong-willed personality and maintains a tough exterior, yet reveals compassion through actions like rescuing Eiko Tsukimi from a suicide attempt and subsequently offering her employment as the lounge's resident singer.

His extensive knowledge of the Three Kingdoms period and enjoyment of playing Go prove crucial when he encounters Zhuge Kongming. Initially perceiving Kongming as an eccentric cosplayer, Kobayashi recognizes the strategist's authentic historical understanding during an interview. Impressed by Kongming's insights, Kobayashi employs him as a bartender and receptionist.

As Eiko's career progresses, Kobayashi initially worries the BB Lounge's limited capacity might restrict her growth. Following Kongming's strategic planning that leads to establishing the Fourth Kingdom record company, Kobayashi chooses to continue supporting Eiko and her associates within this new framework. His mentorship remains significant, later inspiring Eiko during the creation of her song "Hot Chill Hot".

Across various adaptations, Kobayashi maintains consistent traits: pragmatic business management combined with genuine support for aspiring artists. His relationship with Kongming evolves from employer-employee dynamics to a collaborative partnership, grounded in mutual respect for historical strategy and contemporary application.