Joichiro Nishi

Joichiro Nishi (西 丈一郎, Nishi Jōichirō) is a middle-school veteran of the Gantz world, having arrived there over a year before the beginning of the series. While running away from police officers after shoplifting, he fled onto an apartment building roof where he fell to his death. Much like how Kurono started out, he is also selfish and has a Social Darwinist approach to life. Nishi is reluctant to reveal anything about the Gantz or himself, but he runs a web site where he posts information about it (carefully avoiding Gantz's rule about informing outsiders, which would in turn prove fatal). Gantz calls him "Mr. Nishi," which is rather interesting given how informally or derisively he refers to most of the other participants. Nishi is killed at the beginning of the Tanaka/Suzuki Alien mission, but after six months of existing only inside Gantz's memory banks, he is revived by Kaze at Kurono's request following the end of the Oni mission. Ostensibly, Kurono hopes that Nishi will be able to provide information about Gantz to the game players. Whether or not Nishi actually provides any information or if this information has proven useful is yet to be seen. It seems that Nishi and Izumi have a past relationship as "teammates" before Izumi's memory was wiped and he won freedom. It has not been revealed if Nishi and Izumi were friends or just acquaintances forced to fight Aliens together by Gantz. It is revealed that Nishi got 75 points after Nurarihyon was killed, presumably from killing the Tengu alien. Once the scoring of the Nurahiyon mission ends, he reveals the 'Katastrophe' keyword, by giving it to Gantz. This makes Gantz show a countdown to what appears to be the time remaining for "the humanity to lose everything". What this means, is unknown until now. Voiced by: Masashi Yabe (Japanese), Chris Patton (English)

Source: Wikipedia