The Onion Alien Mission is the first mission we see in the series. The mission last from chapters 5 to 18 of the manga, episodes 2 to 5 of the 2004 anime series. In this arc, Kei Kurono, Masaru Kato and Kei Kishimoto die and find themselves for the first time inside the Tokyo room being forced to hunt and survive mostly dangerous aliens.
The game area is a part of Ichinomiya, Tama-shi, Tokyo and includes several blocks of houses and a part of Ichinomiya park. Once you reach the border of the Game Area you hear a ringing noise and if you leave it the bomb in your head activates and you die.
In this mission, the alien that appeared on the Gantz screen was the child alien only. He was the supposed target of this mission. However no one got points for killing it. Instead Joichiro Nishi was awarded 3 points for finishing the Adult Onion Alien after Kei Kurono has beaten it.
- Kei Kurono
- Masaru Kato (Kato-cha (lol))
- Kei Kishimoto (Naked Girl)
- Joichiro Nishi (Middle School Kid)
- Masashi Yamada † (Glasses)
- Goro Suzuki † (Politician)
- Kiyoshi Yoshioka † (Yakuza 2)
- Hiroshi Hatanaka † (Yakuza 1)
- Takashi Inamori † (Blondie)
- Rice (Butter Dog)
† = Deceased during missions
After being brought to the Tokyo room the new hunters question everything what is going on before being transported to an empty street, after learning they have to kill the Kid Onion Alien. Initially they all plan on going home until Nishi tells Masashi Yamada that they are part of a game show and can win ten million yen if they participate and kill the Kid Onion Alien, which Yamada blurts out to the others. Nishi then makes the statement to the group that his father is the producer as he starts explaining the apparent game show they are now a part off. He tells them they were hypnotized before they were supposedly killed by someone who talked to them before their death happened. This makes Kurono thinks of the old lady who talked to him in the station. The Yakuza Kiyoshi Yoshioka, Hiroshi Hatanaka, Inamori and Yamada and even the dog then eagerly run away towards were Nishi tells him the alien is, slowly followed by him. Yamada finds the alien first and is quickly joined by the others. They then figure out they have to shoot it, while the alien gets mucus on them because he is frightened, which allows it to get away from them by jumping off a balustrade. Tt lands right in front of Kurono, Kishimoto and Masaru Kato whom helps it up asking it if it is okay, but it runs away as the other hunters come running towards them and after it.
As they catch up to it they blow up a wall before cornering it. They then all shoot at it killing it while Kato whom catches up tells them not to kill it or finish it off. But they ignore him. Masaru then questions if it is really a TV Show and gets Yamada to touch the remains which makes him vomit. Inamori states that it wasn't human while the yakuza grab the torso wondering what they must do with it. They then find out that other people can't see them or the alien remains at all, just the broken wall is visible to them. They then wonder if they are really dead as the Adult Onion Alien arrives behind them. It then looks at his sons remains and starts crying and angrily stares at them which pisses of Hatanka who grabs its shirt.
Hatanaka still stares down the Onion dad which shouts at him and then gets headbutted by Hatanaka who breaks open his own head on the concrete like bone density of the onion alien. The four of them then starts shooting it with their guns, it however doesn't move but grabs Hatanaka's head instead and screams at them in its own language about his son. Inamori then shoots at it on full blast, but the alien blocks the shot with Hatanaka's body, who gets angry about being shot before his torso explodes killing him and splattering them all with even more blood and guts. Onion dad then remembers his son and crushes Hatanaka's skull. This scares them and Inamori starts shooting as does Yoshioka who's arms get grasped by the onion dad is ripped off as Inamori stomach gets ripped open while Yamada is still shooting at it and also gets his armed chopped off. It then looks at Kato ready to strike him but he gets shot by a regular gun several times by Yoshioka who thinks he killed it and dies. Kato looking at all the carnage states he doesn't want to be there, then the Onion dad stirs and stands up in no time ready to finish Kato off. The dying Yamada then imagines an entire TV Crew telling him he is awake now, relieved he looks down to find out it was a delusion and that his arms are gone, he then screams but remember waking up inside the Tokyo room and relieved he dies thinking he will be back there. Masaru then tries to communicate with the onion dad stating he knows how he feels, failing to communicate with it he points the Y-gun hoping it will not kill him but before he can do anything he is attacked and barely dodges it claws, which previously killed two people in one swipe. He then puts the gun to the alien's head wondering if he will survive if he shoots, he then lowers it saying he can't kill it. It then attacks him and smashes him over a balustrade making him fall down a hill.
Kishimoto and Kurono then come across the Onion Dad and the carnage he has wrought. Kurono tells Kishimoto they should run away but it sees them and starts chasing them. Kurono then notices the girl is gone and see the alien chasing her and he remembering he would protect he gets its attention and manages to get it to chase him instead. While running away from it, it gets hit by a car but the drivers however can't see it nor him. Not even when standing right in front of one of them but who does notice there might be an invisible person there. The onion dad then stands up and smashes the hood of the car and jumps up after Kurono whom has started running away again. Thinking he will die again Kurono remembers his family wonder if they will be sad when he is gone, he then feels that Kato would be sad if he was gone remembering their childhood together as the alien corners him, he remembers how when he was young he got away from a bully in the same situation, he then runs towards the alien and slides underneath him, just like he did back in the day with the bully. He then runs away again. Kato is then seen waking up at the bottom of the hill still alive.
Kurono is still running away from the alien and he learns while he runs how to tap into the power of the suit. Meanwhile wondering if Kato is really dead. He then remembers jumping a flight of stair in his youth and using the suit he now jumps over a giant row of steps going up the hill. Which is seen by Kato who was walking towards it, whom exclaims "Awesome". Wondering how he jumped so high, Kurono's had a rough landing, but he is alright. The alien regretfully has followed suit and quickly crawls down the stairs and stands menacing before him, Kato remembering Hatanaka's dead hurries over towards Kei as the onion dad is about to grab Kurono's neck, luckily Kato gets up behind him and takes it into a strangle hold. It then cuts into Masaru's arms making him release it from his grip. Kato then gets knocked down by it, clutching his sliced arm with broken wrist. The alien then grabs Kato upwards and looks at him ready to kill. Kurono sees this and using the suit he gets up and charges at the alien and he manages to grab both its arms without getting injured, Kato meanwhile remembers the deaths of the others and tells Kei to kick its ass.Kurono then breaks one of its wrists and stares it down. The alien then grabs his head with its other hand as his skull gets squeezed, Kurono cocks back his arm and punches the alien in the gut with all his might, which causes it to release him, Kei then punches it in the face with all his might and he keeps hitting it trying to take it down.
Thinking he beat it senseless he hurries over to the very wounded Kato, who tries to say it was his fault since he couldn't protect the kid alien. Then the onion dad echoes the same statement saying he is sorry and he will give him his onions. A hand with a Y-gun then materializes shooting at the alien, the triangle shot then wraps around the alien and pins it to the ground. A smiling Nishi then steps forwards towards them. Kei asks him were he was and Nishi responds that he was close by following everything> He tells them they made it in time and that he will give him the points meaning Kurono can shoot it with his gun and to pull both triggers in order to do so. Kurono asks if it will die if he shoots it which Nishi confirms. He then eggs him on to do it, saying he is just like him and that looking at death people makes him happy just like him. Kurono lowers his gun and tells him to fuck off saying he is nothing like him and he walks away.
Nishi then shoots it with the Y-gun and the alien gets transferred away and send up into the sky. Nishi then explains that the Y-gun is for sending and his is for killing. Kurono then asks him if he knows what this is about and Nishi answers he doesn't know everything but he does know a lot more then him. He then explains they will go back to the room and afterwards you will be free to go home. Kurono then thinks about going home and asks if they can bring back Kato. Nishi tells him that only the living can go back to the room, but that Kato if he is still alive might still survive. Nishi is then send away as Kurono frantically tries to wake Kato up and get him to remain conscious. So ends the Onion Alien Mission.
- Kei Kurono (earns 0 points)
- Masaru Kato (severely wounded, earns 0 points)
- Kei Kishimoto (earns 0 points)
- Joichiro Nishi (earns 3 points)
- Rice (earns 0 points)
- Gantz's apartment bears a strong resemblance to a famous building in the Ebisu area of Shibuya.