Series: Touhou & Kaiji - Gambling Apocalypse: Koishi (warugaki)

Koishi wanders into the games of the Teiai Group. Chaos ensues.

Part 1: Here
Part 2: The Chronicles of Hell's Middle Manager: Tonegawa
Part 3: Gambling Apocalypse: Satori
Part 4: Gambling Touhou Record: Koishi