This contains Gantz/Osaka, Gantz no Moto and Gantz/Nishi. Gantz/Osaka is a special (limited edition) 3 volume re-release of the Osaka arc with two entirely new chapters. Gantz/Osaka falls under Phase 2 (Katastrophe) of the Gantz manga series and details the missions of the Osaka and Tokyo teams as they face off with the Nurarihyon Alien. Gantz no Moto is a special chapter that has Hiroya Oku telling the story on how he got into the manga business and what films influenced him. Gantz/Nishi is a one-shot chapter showing the life of Nishi.