Kei is currently in a final showdown with Eeva Guna, a giant alien set to avenge his brother who was killed by Kei early in the Katastrophe Arc of Gantz.
Kei Kurono is an ordinary teenager from Tokyo, Japan. His life changed upon reuniting with his childhood friend Kato Masaru. They both attempted to save a homeless man who fell on a train track. Kei and Kato were able to save the man, but an express train ran them down. This is when Kei was transported to a mysterious room and forced to become a Gantz Hunter against his well.
Kei began as a typical selfish and horny teenager in the beginning of Gantz. His primary focus was to have sex with Kei Kishimoto, a girl forced to became a Gantz Hunter on the same day as Kei. He spent much of the first arc of Gantz trying to show off as well. Eventually Kei began to change after witnessing all the hunters on his team get slaughtered. He no longer wanted anyone to die when forced to become hunters. This was a trait adopted from his good friend Katou. Kei spends the rest of the Gantz series teaching newly forced hunters how to survive. Many hunters that enter the world of Gantz in the Toyko district view Kei as the undisputed leader of their team. He is eventually viewed as a hero to the entire world when a full on alien invasion occurs.
Onion Alien Mission
This was Kei's first mission and the target was a green kid that liked green onions. Many believe this all a joke. A veteran hunter named Joichiro Nishi used this to his advantage. He told everyone they were playing a game and would get a reward for killing this child-like target. Kei, Katou and Kishimoto were the only ones that found the target disturbing. Kato tried to halt the slaughter but was too late. This led the true target to arrive and find his son murdered by the humans. The unnamed target(Boss Onion) began to kill everyone present. Kei arrived late and became a new target. He fled with Kishimoto only to leave her unaware of his abilities in the suit. Boss Onion caught with Kei seeming to ignore the girl. Kei struggled at first as fear gripped him. Kato came to his aid but was mortally wounded. This lead Kei to fully activate the suit and defeat Boss Onion in melee combat. Although Nishi dealt the final blow to gain the points for the mission. All others were dead leaving Kei,Kishimoto and Nishi to return to Gantz's room. Kei and Kishimoto were tearful until Kato return as well. The trio learned as long as an inch of life is left in completing a mission that they would return as they left in perfectly new copy bodies. After the mission Kei was somewhat relieved to be alive and decided to take the suit home with him. Kei used the suit at school to fend off bullies now targeting him for money. Upon coming home he found a homeless Kishimoto. He discovered that Gantz mistakenly selected her. Kishimoto slit her wrist to die in real life only the original body survived. Kei allows Kishimoto to stay with him and they live together until the next mission summons them back to Gantz's room.
Tanaka Alien Mission
Kei began this mission without his gantz suit as he took it home and wasn't wearing it during the transfer to the Gantz room. He spent the beginning of the mission fearing for his life. Kei felt there was no way to survive without a Gantz Suit. Kei attempted to steal a suit from a member of a biker gang. He was caught by the gang members and suit was with held from him. Kei was transferred to the mission area. He became more frantic after witnessing the death of Nishi, who died despite having a suit. A series of events led Kei to meet the primary alien boss of the mission, an unnamed massive bird-like creature with a breathing apparatus. Kei became the bird-like alien's primary target. Kei managed to defeat the alien against all odds. He proved to be resourceful even without the aid of the Gantz Suit at this point. After the mission things take a turn for the worse to Kei. He learns that Kishimoto is in love with Kato for saving her life among other things. She longer wants to live with Kei and this upsets him a great deal.
Buddha Alien Mission
Kei is effected heavily by events with Kishimoto leaving his place. Time passed and Kei longed now to go to Gantz's room. Kei is sure to bring his suit this time and intent to kill every alien before him. He finds a new batch of hunters once again replacing those slain. Although this group has been in presence of priest claiming to have the answers. All goes as normal until Kishimoto arrives and ignores Kei for Kato's attention. She once again brings up how she wanted to contact Katou outside of Gantz. Kei can't take this situation and heads to the back room to be alone. This draws the attention of a new female named Sei Sakuraoka who finds Kei crying. Kato begins trying to tell his tips of the mission versus the priest and his methods to ascend to heaven. Kei and Sei begin to talk on their own as she is attracted to Kei.Kishimoto comes upon the pair as it is the area where she changes. She leaves with Kei wanting to forget her. This mission begins and the enemy is larger than before. Others are cautious but Kei goes into action impressing the new hunters especially Sei. Kei is able to take out both the initially presented Buddha Aliens and even a much larger one that is near 10 stories high. He is very reckless while doing this and nearly gets other hunters killed. Kei and the other veterans thought it was over but more Buddha Aliens were present. Kei watched as many were slaughtered. He was enraged as Kishimoto died saving Kato and suffered critically blows that severed parts of his body. Katou and Sei were the only two left to face the real boss of the mission an alien disguised as Kannon the Goddess of Mercy. Katou left to retrieve a Y-Gun that Masanobu had in his possession. Sei remained to protect the incapacitated Kei as she wanted him as her new boyfriend. Kei discovered Sei was proficient in martial arts and the Gantz Suit boosted her abilities. She was able to injure the Kannon alien. Sei was eventually killed as well before Kei's eyes. The Kannon alien ignored Kei seeing him as dead already. Kei return and statue like alien. He was fighting on Kei's level at this point and managed to severe several of the Kannon alien's many arms. Unfortunately Kato was impaled by the dying alien to perish with the creature. The mission was over and Kei was the only one to come back alive. Katou,Kishimoto,Nishi,Masanobu,Sadayo(Sadako)and Sei were all gone at this point.
Three missions have been completed with Kei surviving the deadliest one yet. Although he was the only one to return and falls into a minor depression. Matters grow worst upon crossing the real Kishimoto as Kei spent time around her Gantz copy. He attempted to conversate but ended up making himself to seem like a stalker. Soon after this Kei meets a new transfer student Izumi Shion. Kei ends up being stuck with the guy to show him around. Kei doesnt think much of him but everyone else believe Shion is the best thing to come along. Shion finally draws Kei's attention by bringing up his interest in a website called The Black Ball's room. Kei pieces together Nishi must have created the site and exploited him as well. Kei's name is the only one mentioned by Nishi on the site. Kei is now cautious of Shion and fearful as Gantz blows up heads to anyone that reveals his existence by word of mouth.
Chibi Alien Mission
Kei survives the light interrogation by Shion and a mission is his reward. Only this time Kei finds himself alone as Gantz has not replace the fallen for unknown reasons. This puts Kei in a state of panic as he is to face the aliens alone for the first time. Kei is delusional in facing the first alien and having flashbacks of his friend Masaru. Kei is then surrounded and discovers the Chibi Aliens are capable of telepathy. They speak into his mind with threats of revenge for their fallen comrade. Kei has other plans and begins to fight. He is quickly outmatched by the group of Chibi Aliens. The arms of Kei's power suit are ripped off but this does not slow him at all. He regains his weapons to finish his oppressors off. Things grow grim in facing one last Chibi Alien that has watched and learned all Kei's move. This final boss begins hunting Kei throughout the battlezone. Luckly time runs out and Kei returns to Gantz's Room intact. He also lost all his points for not completing the mission.
Kei was terrified of the Chibi Alien as he was totally outclassed in melee combat. Kei resumes his daily life awaiting the next mission to come. Things change as he ends up meeting Tae Kojima based on a dare to ask her out. It turns out the girl had a crush on him from afar. Kei has nothing better to do and has never had a girlfriend so he decides to tolerate her. Then without warning a haunting voice is in Kei's head. The Chibi Alien is at his school and want revenge for the death of his comrades. Kei could care less of those being killed and leaves before the alien actually finds him. Kei locks eyes with Tae in leaving her in the classroom where the alien is now present and starting to kill. Shion survives the slaughter with Tae cringing in a corner. He fights the Chibi Alien in human flesh aware the guy is not human. Kei suits up and decides take respobility for the alien at his school that obviously came for him. The local authorities are present when Kei decides to save Tae as the alien didnt notice her yet. Things grow worst as the creature learned Tae is important to Kei upon saving her from harm. The police SWAT arrive to deal crucial damage to the Chibi Alien. The SWAT members underestimate the alien believing a weird human. They are killed and Kei surprises the alien to kill it with the X-Gun.
Kei gets a long break from Gantz. He uses this time to get to know Tae. The girl had a crush before the Chibi Alien incident. Now Tae is head over heels in love and spending her focus on Kei. 2 weeks go by with Kei and Tae having stick with each other being the survivors of the school massacre. Kei also spends time on Nishi's website to learn more about Gantz. Days go by and all is normal for Kei until a new challenge comes. A mysterious guy has been going to every school and fighting the strongest student their. Kei originally used his suit only to avoid harm from bullies. They have now pegged Kei as the strongest as none could hurt him. Tae is fearful in watching Kei be lead away. She ends up following to see Kei meet the man known as Kaze Daizaemon. The fight begins and Kei is quickly pummeled by the veteran combatant. Kei is fearful wondering if the man was another alien. Kei uses the might of the suit to knock out Kaze. Tae is relieved and Kei leaves with her. He is unaware of being the first to defeat Kaze and earns his respect. Kei and Tae continue their days learning more about each other.Shion is back in Kei's life and trying to prove the horrors of reality. Shion comes first trying to steal Tae away only to learn the girl is truly in love with Kei. This lead to a brief dream of Kei believing he made of Tae's existence and was alone again. He woke with her in his arms and now determined to escape the grasp of Gantz at all cost. Kei begins doing more research when he gets a call from Shion. It is about a guy resembling Kei at the school leading him to believe another alien was about to move. This was a ruse by Shion to get Kei to meet him alone. Shion has a gun with him and rambles on about the black ball and belief he was once in the room. This is when Shion shoots Kei at point blank. Kei luckly brought his suit and confirming Shion's beliefs of the black ball's room. He now plots to return to the room and be like Kei as a hunter. Kei discovers Gantz actually sent Shion a message to 'send' as many people as possible to the room. Shion reveals means to go on a killing spree and welcomes Kei to stop him. Shion resumes to shoot at Kei with no effect. Kei is unsure what may happen upon shooting a human. Shion walks away with Kei wondering if he will really kill for Gantz. Kei grows more concerned as Tae is tasked to interview Shion who is now the most popular at the school. Shion put a big front for Tae. Kei knew the guy was a real monster and had to watched closely.Shion revealed a plan to kill at the city of Shinjuku. Kei felt it a bluff as Shion wanted to be killed by Kei. He was going to ignore it until learning Tae had been invited to Shinjuku by Shion and his girlfriend.Shion wanted Kei to face him and without the suit this time. Kei makes way to rescue Tae. He ponders over Shion's goal. Kei arrived at Shinjuku to find many have been slain. Among the slain are Kaze Daizaemon, and two characters named Sakurai Hiroto and his mentor Sakata Kenzou. Kei finds Shion and the unconcious Tae. Shion wanted a duel to see who was the best and should be Gantz's champion. Shion was much faster and able to shoot down Kei. He was prepared to kill Tae as well but is blown apart by the dying Kei.Once again upon death Kei returns to Gantz. He discovered Shion alive as well with a panda hugging him.Shion knocks out Kei as Gantz addresses a room full of people unaware Shion was the masked killer. Kei finally came to with a mission commencing. He didnt have he suit again and planned to find a safe haven until the end. Gantz had other plans and demanded Kei to achieve a certain amount of points or he would die for real. Kei manages to brief the remaining two people, teen idol Reika and old man Yoshikazu Suzuki. Both listen to Kei and dawn power suits. This time Kei would be facing creatures of a prehistoric nature.
Kappe Alien Mission
This is more of a survival of the fittest mission set up by Gantz. Kei was by himself the last couple of missions against the Chibi Alien and Shion. This new mission brings loads of new characters to the game. Kei has a new aspect on life and his part in Gantz by this point. He tries to be more like Masaru and tries to explain the situation to a couple of people. Gantz decides to put the pressure on Kei once again. Kei must earn a set amount of points in order to return to the room alive. He decides to actually look around the room for a change to find a monocycle. Kei decides to utilize the vehicle since he was in Gantz without his suit for a second time. Kei is teleported to find Yoshikazu(Yoshi), Reika, and Kaze waiting for him to arrive. It is at this point Kei realizes who Reika is upon a closer inspection. He regains his composure to focus on the mission at hand. Kei takes off with the old man, Yoshi to begin the hunt. Kei finds out the targets are aliens resembling dinosaurs, the Kappe. Kei constantly has remind himself to brave without his suit. He once again shows his agile nature by avoiding injury from one of the Kappe dinosaurs. Things improve for Kei after explaining to Yoshi how the suit works. They manage to decapitate one of the aliens but it still lives. Kei is then left alone as Yoshi flees in fear as the alien is also talking without a head. Kei does his best to survive until Yoshi returned to fully utilized the suit. Kei finishes the alien by locating the heart and killing it. He is forced to retreat in facing a pair of Trex aliens. Kei ends up having to fight them anyway as he saw others being targeted. Kei is able to kill one with his rifle. Shion kills the other one. Many aliens emerge with the a large brontosarus among them. Kei opts to protect everyone with suits from many raptor aliens. Shion goes for the brontosarus ignoring everyone else. Kei is successful in killing the raptors while Shion is in need of help. Kei takes on the brontosarus and reflects on all that he has been throught. He realizes that Tae is a person he wants to return to and knew that losing was not an option for him. Kei kills the boss and ends the mission. During transfer back to the Gantz Room Kei finds mysterious individuals approaching the scene. They are the Vampires, and desire to kill the Hunters that once targeted them. Out of the nearly 30 people that started the mission only Kei and the new main characters Sakurai,Reika,Yoshi,Inaba,Kaze, and Shion returned. Kei ends up with the most points and gains admiration from all but Inaba and Shion.
Kei returns to Tae first thing after leaving the Gantz Room. He resumes his typical life and missions seem to be on hold. Kei spends his days being ridiculed by teachers and fellow classmates for his laziness. He gains the nickname Daytime Lantern. Kei spends free time using the Gantz Suit to perform superhuman feats away from prying eyes. Eventually Kei is surprised by a visit from Reika and the others from the room except Shion. They see Kei as a leader and want training if they were to return to the Gantz Room. Kei spends time with Tae and eventually runs into his younger brother Akira Kurono. Tae ends up confronting Kei about his secrets. She brings up the Gantz Suit but Shion saves Kei. Shion explains that if Kei was to share everything with Tae his head would explode. Shion also advised Kei not to inform the poice he was responsible for the Shinjuku Massacre. Kei is forced to pose as best friends with Shion. They end up double dating with Tae and Shion's trophy girlfriend Ryouko. Kei isnt aware the Vampires are aware that Shion is a Gantz Hunter from his past life. The group head for Shibuya for a daily outing. This is where the Vampires ambush Shion in large numbers. There werent aware that Shion was wearing his suit like Kei under his clothes. Kei plays the Daytime Lantern and doesnt help Shion. He covers Tae from any harm. Afterwards Shion just leaves in all the confusion. Things seem to return to normal as the Vampires have no interest in Kei. He spends more and more time with Tae. Another twist comes from the super idol Reika who ends up having a crush on Kei. He goes joins her for dinner and ends up in a magazine as Reika's love interest. Kei always wanted someone like Reika but was now with Tae. He spends a while debating weither to break up with Tae. Kei saw that Reika was prettier,smarter,sexy, and also knew his double life as student and hunter. Kei decides that Tae means more to him but Tae finds out about Reika and breaks up with Kei(He loses cool points by crying like a girl a few days later over Tae). Time passes and Kei gets a tingle at his back that is a sign for the next mission from Gantz.
Ring Alien Mission
The new foes are revealed as dark warrior like creatures on horseback referred to as Ring Aliens. Kei finds Reika and other survivors from the mission doing fine. There are also new people. A bunch of shady characters but it doesnt stop Kei from explaining the rules to them. He makes sure everyone is in a suit and the hunt begins. The Ring Aliens are big as the Kappe Alien boss. Kei and the new veterans use their teamwork from practice to kill one of the aliens. Shion kills the other by himself. Kei is surprised to find Tae on the scene but cant see anything that is going on. Kei plans to ignore her but Reika calls attention to third Ring Alien aimming for Tae. Kei is forced to knock her out the way. Even though Tae cant see anything. She knows it is Kei who was on her. Kei targets the alien and manages to decapitate the foe with its own weapon. All three aliens are dead and everyone survives. Once again Kei gets more points than everyone else. Kei praises all for doing their best. Everyone attempts to leave but the door doesnt open this time. Gantz has another mission and Kei is first to see the target is Tae.
Kei's ex girlfriend Tae is targeted by Gantz. Reika and Shion are the only ones aware Kei knows this target. Kei gets Gantz to send him out first. He rushes home to cover up his suit with normal clothes and leaves to find Tae before the others. Kei meets with Tae to protect her as Shion cares only about completing his mission. Luckily Sakurai,Reika,Yoshi, and Kaze have befriended Kei. They dont want to kill Tae if Kei is trying to protect her. This divides the current hunters between those loyal to Kei and those afraid of Shion. Now that Tae is apart of Gantz Kei finally reveals everything to her without his head exploding. Kei takes Tae to a place he feels is safe. He uses his stealth technology on the approaching evil hunters that know little of how the game works. Tae is left out in the open as bait. Kei ends up killing one of the evil hunters. He tries to kill another but the suit protects him. The remaining evil hunters flee as they cant see what is attacking them. Tae wants Kei to stop protecting her since they werent dating anymore. Shion arrives as the evil hunters went to bring him to the location. He tells Kei that Yoshi and Sakata has serious injuries. He wants to kill Tae and end the mission to save the others(He doesnt care but knows Kei does) Kei refuses and Shion goes invisible. Kei goes invisible as well. All the others see are rifle blast and sword swipes. It ends when Reika puts her gun to an invisible Shion's head. Kei engages Shion again and asks Reika to get Tae to safety. Kei is surrounded by Shion and his group. He manages to leap away and avoid certain death. Kei battles the novice hunters across the rooftops and streets of his home town. He takes out another evil hunter but his suit is damaged from various rifle blast. Inaba arrives to reveal siding with Shion. He strikes Kei down and Kei takes serious injuries with his suit no longer working. Tae comes from around a corner begging the hunters not to kill Kei. That is when Shion pulls a Sephiroth move and strikes the girl down from behind.
Kei cries and Tae cries in his arms. She calls Kei's name and he calls Tae's name. Tae dies and her body is transferred away from the scene. Kei has a delusion about being in bed with Tae. He thought the mission was all a bad dream. He shares some words with Tae. She begins talking like she is saying goodbye and thanks Kei for everything. He wakes up in the Gantz Room surrounded by his friends and enemies. Everyone leaves as the mission is over now. Kei comtemplates suicide with Tae on the mind. For some reason the Gantz 100 point menu comes on(even though nobody has 100 points). It reveals to Kei a secret third option to revive anyone in the Gantz Memory Bank. Kei checks the memory bank to find Masaru,Kishimoto, and Tae were saved as backup copies by Gantz.
The Tae mission is done and everyone is free to relax until Gantz calls for them again. Kei lives with Tae on his mind. Things arent good as Gantz could erase Tae's body but not her existence. Investigations begin on her disappearance. Kei is a prime suspect as he was last seen with her after they were suppose to be separated. People at school believe Tae is long dead. Kei decides to focus now on getting 100 points to revive Tae and Masaru. He goes to the Gantz room to start a mission but isnt allowed inside. Kei is frustrated and goes home to find Reika waiting for him. She wants to know if Kei hates her for letting Tae out her sight. Kei doesnt relpy and goes into his apartment.
Oni Alien Mission
Kei and the Gantz Hunters are tasked with facing the Oni Aliens. He quickly realizes things are different than previous missions. Ordinary people can not only see the targets, but also the hunters. Kei spends much of this mission trying to protect bystanders while eliminating various aliens that had gathered in large numbers. Eventually Kei and Shion faced off against the oni boss an unnamed creature able to generate lightning. Kei and Shion worked together to defeat this enemy. This event allowed Kei and other hunters to achieve over 100 points at last. Kei was shocked when Reika chose to revive Tae for him. Old man Yoshikazu also used his points to revive Katou for Kei. This left Kei with no choice but to use his 100 points to chose freedom and have all his memories of Gantz erased.
After the Oni Mission Kei is seen at the train station where he had original died reading a magazine. It is revealed that Kei did not only lose his memory of Gantz, but he has also lost the memory of his normal life memories that happen when he wasn't in Gantz, this mean that he has lost his memories about the now resurrected Tae Kojima. When Kei goes to school the day after the Oni Mission he is shock, and confused at the mention of an alien attack he is also confused at everyone talking about his relationship with Reika.
Once school is over and, Kei returns home and finds pictures of Tae and him completely covering his bulletin board, and the large picture she drew of him under his bed. Kei, now greatly confuse,and shocked, writes this off as Tae being a stalker. While throwing away the pictures he lift up the drawing and burst into tears and cannot bring himself to throw away the picture not knowing why.
The next day, while at school, Kei is confronted by Tae saying that she has vague memory and thoughts of him. Kei's response to this was telling her she was a stalker ,then he runs away from her. After that incident Kei goes out of his way to avoid Tae at all times, even elbowing her in the eye while running away from her.
Kei Continues thinking she is a stalker until a classmate, tells him that she is his girlfriend now Kei doesn't know what to believe ,that is until upon returning home finding Tae in his room. When he walks in Tae, whose memories had a minor awakening, thinking Kei would be angry with her intrusion tries to run out of the room with her drawing. Before she meet the door Kei grabs her hand, telling that he thinks he has amnesia and he want to regain the memories he had with her, Tae agrees.