According to what Nishi said, Shion appears to have been teleported to the GANTZ room at least twice, and what’s more — the second time, Shion claims to have appeared simply by willing it into reality!
After causing a huge ordeal, he fought Kei Kurono at the Observation deck of the Tokyo Metropolitan Government building in Shinjuku, and subsequently shot each other down using X-guns.
Regarding his first teleportation, the reasons for his being teleported there, as well as the circumstances of his death, are still unknown.
Upon returning to the GANTZ room, Izumi shouted with happiness and jumped for joy.
Standing in front of the GANTZ once again, he remembers scoring 100 points and “clearing” his task.
Also, he remembers his friends that he fought alongside with, but —
Why would someone who completed the missions, and was released from the room, return so enthusiastically — or even think that they wanted to return to such an existence in the first place?
Simply put, Izumi is perfect: good at all sports, strikingly handsome, and always scoring the highest grades at school.
One difficulty might be dealing with women — When a girl who transferred to a new school the same day he did confessed her love to him, he said that he’s bad at talking to girls because his previous school was boys-only, and that he had no sisters.
He was well-liked by his classmates, and described as an “All-around good guy.”
Kurono often compared Izumi with Kato, given that the two of them had an incredibly strong sense of justice.
However, most of his being such a good guy was pretense — a sort of insurance for that which would be carried out later — The Shinjuku Massacre.
In terms of his true feelings, it didn’t matter to him what he lost, be it his girlfriend, the people that he fought side-by-side with — none of that matters.
This is because to him, ultimately, the only person that you can trust in the world is oneself.
During a particular mission, Izumi set out for battle wearing a GANTZ suit and carrying a sword that he’d grown quite attached to. While most would quiver in fear or anticipation, he did so with the stoicism and calmness undaunted.
He once bragged, “I evolved past and gone further than Kei Kurono,” but his braggadocio attitude was dismissed that Kurono survived an insane mission without even wearing a GANTZ suit, and showed a hitherto unseen level of leadership.
The feelings of envy, doubt and resentment toward Kurono would eventually build and build, until they’d explode in a direct and severe confrontation with Kurono, even though he claimed to not worry about the opinions of others.
These emotions would later well-up and explode in the mission of Tae Kojima.
KEY POINT: A portent of Kei Kurono & Shion Izumi doomed to die.
During Izumi’s first visit to the GANTZ room, some destinies were reveal by aliens, namely, the “Catastrophe,” and furthermore pointed to Kei Kurono as a key person, as well as the eventual death of Izumi, which would occur protecting a woman.
Perhaps it was fear and anxiety that made him leave the GANTZ room.
However, those memories and feelings were suppressed by the GANTZ, and his fate shone once more and brought him back to the eternal battlefield.
---- Oku-sensei’s comment:
Similar to the madness that overcame Nishi, Izumi is a person that is attracted, in general, to the world of GANTZ.
The entire comic and story might get a little strange if Kurono and Izumi got too similar-seeming, so I had Kurono grow and progress as a character by going out with Tae-chan, which, in turn, brought Kurono closer to Kato.
But, because of this dynamic comparability, Izumi is sort of a photonegative of Kurono, and his existence ultimately serves to compliment and highlight the Kurono character.