Genre : Gore - Drama - Action - Horror
Gantz is a manga and anime series written by Hiroya Oku. Gantz tells the story of a teenager named Kei Kurono who dies in a train accident and becomes part of a semi-posthumous "game" in which he and several other recently deceased people are forced to hunt down and kill aliens. The missions they are dangerous.
Much to the annoyance of Kei, he and his childhood friend Katou have died, having been torn apart by a train. But rather than finding themselves at the gates of heaven, the duo materialize in a room full of strangers and a giant black sphere known as GANTZ. As if dying once wasn’t bad enough, the occupants of the room are then forced to embark on dangerous missions to kill strange aliens; missions that very few return from. Now, Kei, Katou, and a well-endowed friend must fight for their freedom with an arsenal of guns, high powered suits, and a very low chance of survival.
Main Characters
Kurono Kei:
The story's protagonist, a 10th grader. He is summoned by Gantz, along with Kato, after being hit by a subway train in an effort to help a hobo who passes out on the tracks. In the beginning, he is a rather selfish character who often ends up being the reluctant hero. At one point, Kurono actually enjoys the brutal missions, having a chance to prove his mettle and to use the powers Gantz's technology grants him to decimate his foes, as well as to receive the admiration of his team members, such as Sei or Kishimoto. In the manga, Kurono is eventually regarded as a hero by the other players who look up to him. Kurono himself looks up to Kato after his death.
Kishimoto Kei
Kishimoto first appears naked in the Apartment as her death involved slitting her wrists while in a bathtub. Kurono has a deep crush on her, but she herself has a crush on Masaru Kato; she even sacrifices her life in an attempt to save his in the Buddha Temple mission.
Kato Masaru
He is an old friend of Kurono. He is a noble and heroic person and was inspired by the Kei-chan he knew as a boy. At school, he acts as a guardian to the weaker students who often find themselves bullied, getting himself a bit of a reputation for fighting. He is summoned, along with Kurono, by Gantz. They are hit by a subway train, a consequence of helping a drunken hobo who blacks out on the tracks. Kato and his little brother live with their aunt, but continued abuse toward his little brother and a stressed family situation later cause him to obtain an apartment for the two of them. Frequently, Gantz addresses him as "Katō-cha", after the Japanese comedian, Katōcha. During his third mission, the Buddha Temple mission, the final boss kills him.
Images of the room where the black ball resides

Weapons
X-Gun: The most frequently used weapon of the Hunters. The X-gun is a small handgun-sized weapon, that gets its name from the four protrusions around the barrel that spread out like an "X" when fired. Also, it has an X-ray monitor in the back.
X-Rifle:This weapon is similar to the X-Gun in almost every respect in terms of functionality. However, the X-Rifle is meant for longer range, has higher accuracy, and a sniper scope.
Y-Gun:The only non-lethal weapon in the Hunter's arsenal so far. It is a handgun-sized weapon that has the same lock-on capabilities of the X-Gun, but rather than fire out a lethal payload, it instead launches a homing net that securely ties up the target with a strong wire and then buries the points of the net into the ground. Once this is done, the target is "sent" by means of teleportation to an unknown point in space.
Gantz Sword: The only melee weapon revealed so far. It is a katana-like weapon that is usually in a closed hilt-only state. When in use, an incredibly sharp blade extends from the hilt. It can extend without loss of durability and it is unknown if its length is limited; currently it has only been extended to roughly 30 feet.
Vehicles
Gantz Bike:A type of monowheel and the only vehicle provided by Gantz so far. It doesn't seem to possess any attack ability, but can travel at a great velocity. It made its first appearance in the Dinosaur mission, in which Kurono and the old man used it numerous times to pursue their enemies. It has a second appearance in chapter 243 when two Gantz members from the Osaka team enter the battle riding on them. The Gantz Bike is also present in the Gantz video game as part of a prize after reaching 100 points.
Theme songs
Opening
*Super Shooter by Rip Slyme
Ending
*Last Kiss by Bonnie Pink
Gantz (opening - ending) on youtube:
http://www.youtube.com/watch?v=x53MUtFAL34