Gantz is the name of the man inhabiting the Black sphere in the Tokyo Room. He is a clone of a random person used to provide an interface for the Hunt System. Every Black Sphere around the globe is controlled by a clone of the same unknown man.
Gantz is completely bald and pale, with an average height.
Gantz's personality as a person is unknown, however when inside the Sphere his humour is dark and acidic, calling the Hunters pejorative names such as "Bitch", "Titties" and "Homo" in their profile screens, and often commenting on how poor was their performance in the Game when giving away the points. Whether this trait is shared by every clone or it is just the Tokyo Clone sense of humor is unknown.
The man that resides inside the black sphere of the Tokyo Team is called Gantz. Other teams refer to their person differently.
Onion Alien Mission
Tanaka Alien Mission Arc
Buddhist Temple Alien Mission Arc
Oni Alien Mission Arc
Nurarihyon Alien Mission Arc
As of beginning Chapter 297 - "Stirrings Within The Black Sphere", "Gantz" is seen fully for the first time appearing outside of the black sphere. After a mission everyone leaves, but Reika forgets her clothing so she returns. She finds Gantz outside of the ball. Having earned enough points for the hundred point menu after the last mission, she asks Gantz to use it to create a second Kei Kurono (a copy of the original) for her own selfish reason. He agrees and does this.
Italian Alien Mission Arc
The Invasion Begins Arc
Alien Ship Takeover Mission Arc
United Rescue Arc
During the event that is claimed to be the beginning of the "Katastrophe" phase, in chapter 329 - "Transcendence" Gantz helps the Tokyo Team by removing the bomb chips that are situated in their heads. During Katastrophe, the Tokyo team goes to see him, and finds Nishi there talking to him already, they quite familiar to each other. He agrees to help them, and broadcast Kurono's message of recruitment throughout the other black spheres in order to gather a group for mission in chapter 329 - "Rebel Forces". In beginning chapter 335 - "Rescue Ships Passing In The Night", Gantz plays a role in retransmitting the human detainees outside of the alien spaceship and into safety.
Gantz is last seen in Chapter 342 - "The Apartment Of The Fallen Falls Apart", when it is hacked and attacked by a mob of unknown insectoid assailants.
Destroy the Tower Mission Arc
The Final Challenge Arc
Abilities and Powers
Gantz and his brethren are the only people who can fully control all of the Black Sphere's abilities. Others are shown to teleport others to some degree, but only Gantz can resurrect someone, upgrade the Game's weaponry and end someone's participation in the game.
"Your lives are now over, you bastards. What you do with your new lives is up for me to decide. So there you have it..."