Saito Sejima (世島 犀人, Sejima Saito) is a character mentioned in AI: THE SOMNIUM FILES.
Saito is the son of So Sejima and his late wife, who passed away in maternal death. Saito works as a representative for an unnamed Non-Profit Organization. During the year 2019, he lives abroad outside of Japan, having gone on a soul-searching journey around the world.
Saito Sejima is a young man standing at around 184 cm tall. In his 20s, he has a ruffled set of light brown hair, and a pair of green eyes. As the son of a prominent politician, he wears a navy-blue blazer on top of a white jacket, and a dark blue turtleneck shirt underneath.
Not much is known about Saito Sejima's personality. The small snippets of information about him come from his position as a representative for an unknown Non-Profit Organization, most likely in affiliations with So Sejima's various investments and endeavors. His travels overseas are described as a form of soul-searching by his father, although the details of his journey and what he seeks in his "soul-search" are unclear.
Saito is also described as having an interest in fireworks, and often makes references to them, viewing them as a fragment of time frozen in place and admiring the chemical composition that creates the explosion. It's implied that Saito spent a portion of his youth drawing pictures of animals and nature, and reading books on bugs and insects. When he was a child, Saito had an attachment to his father, the only family he had left, since his mother passed away in child birth. This attachment has given him conflicted feelings about So's endeavors outside of family matters, including So's young mistress.
- "A brilliant, glimmering fragment of time. The flash begins as a perfectly-ordered chemical reaction... that melts into chaos. Human lives are the same, are they not? As is the universe itself..."
- –Saito Sejima, describing fireworks
Saito is the son of So Sejima and his late wife, who passed away in maternal death. Saito was born with a brain dysfunction that left him unable to properly secrete oxytocin, making him unable to to feel pleasure outside of murder. At 24 years old, he served as the murderous half of the Original Cyclops Serial Killer, and at 30 years old he is labeled as the New Cyclops Killer.
In the Lemniscate channel, Saito appears as a parasite inside Iris Sagan, starring in 4 of the channel's videos from "A-set's GDC All-Access Convention Report!" to "This Is Your Idol." In the Impostor/Saito Timeline, from March 20th, 2019, Saito body-swaps into her body, and by April 24th, 2019, he body-swaps with someone else and kills Iris live on stream.
Story (AI timelines)
Saito Sejima was born on March 1st, 1989 to So Sejima and his wife. His mother died in childbirth, leaving him with only his father. At some point he was found to have a brain deficiency that prevented him from producing oxytocin, but was never treated. Because of this, he was unable to experience "love" in the typical sense, but he discovered that he could experience a substitute—his brain would release a flood of dopamine and endorphins whenever he committed murder. As a young child, he would kill small animals. However, he eventually grew a tolerance to it, and decided his next step would be to kill another person.
Murder of Manaka Iwai
In 2001, at age 12, Saito overheard his father going to meet with his mistress, Manaka Iwai, at the Harbor Warehouse District. Feeling that she had taken his father's affection from him, Saito chose her as his target, and followed So in a taxi. As Manaka began to leave, Saito rushed out from hiding and stabbed her repeatedly in the back. In order to keep his political career from being destroyed, So hired Rohan Kumakura and the Kumakura Gang to cover the murder up and silence anyone who knew anything.
In the years that followed, So continued to cover up Saito's crimes to keep his public image clean. At age 21, Saito suggested causing an explosion at the Kabasaki Chemical Plant and using it to make So rich.
Collaboration with Rohan Kumakura
In 2013, at age 24, Saito met up with Rohan Kumakura. Rohan proposed a plan to collaborate on a series of murders—Rohan would find targets for Saito, in exchange for getting to keep the victims' right eyes. Over the course of several months, Saito killed four women and left their bodies in Akikawa Valley. After the bodies were found and an investigation began, Rohan sent a letter to the police calling themselves the "Cyclops," along with a photo of one of the victims as proof.
In November 2013, Falco Psynced with Rohan and swapped bodies. In Rohan's Somnium, he witnessed the Cyclops Serial Killings and discovered Rohan and Saito's crimes. Eventually, Falco (in Rohan's body) visited the Sejima Residence to speak to Saito with the hopes of bringing him to the police. Saito explained the details of his crimes, but he also quickly realized he was not speaking to the real Rohan. With a force of So's bodyguards, he kidnapped Falco and took him to the abandoned chemical plant in the Kabasaki District.
At the chemical plant, Falco confessed everything about the Psync Machine and the body swapping. Saito, intrigued by the Psync System, ordered the Prototype Psync Machine stolen and brought back to the chemical plant. After a few days, Saito obtained the prototype, ripped his own left eye out, and began the Psync with Falco. However, the Psync failed, causing only Saito and Falco's consciousnesses to swap, while their memories were left behind. Falco escaped from the chemical plant in Saito's body, leaving Saito behind in Rohan's body.
Time in Mental Hospital
After the body swap, Rohan was put on trial for shooting Hitomi Sagan. Since Saito was in his body and the Psync had given him amnesia, he was declared insane and sent to a mental hospital instead of prison. There, Saito began to slowly regain his memories. One day in 2018, he finally remembered everything, and broke out of the hospital.
Return to Tokyo
Saito sought out Shoko Nadami and brought her to the chemical plant, then used the prototype Psync Machine to swap bodies with her. Shoko, finding herself in Rohan's body after waking up, panicked and committed suicide. During the year that followed, Saito spied on Kaname Date, gathered information about those close to him, and plotted to take his original body back from him.
Roughly one month before the game's events, Saito visited #89 at Fuchu Prison. Saito did not directly identify himself, but Rohan realized who he was. While in the waiting room, Hitomi spotted him.
On Friday, November 1st, 2019, around 4:00 PM, Saito called Renju Okiura to the chemical plant using Shoko's body. There, he put Renju to sleep, removed Shoko's eyeball, and used the prototype Psync Machine to swap bodies. In Renju's body, he stabbed Shoko's body to death with an ice pick and ate her removed eyeball. Around 8:00 PM, he drove the body to Bloom Park using an abandoned subway line, tied the body on one of the merry-go-round horses, and used Renju's phone to send a NILE message to Mizuki Okiura calling her to the scene.
New Cyclops Serial Killings (Branch A)
On Saturday, Saito called Iris around 5:00 PM to meet him at Sunfish Pocket. She arrived around 6:00 PM, and Saito asked her to come with him to the chemical plant. He put her to sleep on the drive there, removed Renju's eyeball, and used the prototype Psync Machine to swap bodies. In Iris's body, he strangled Renju's body with a rolled-up apron and ate his removed eyeball. He placed the body in an oil drum and put the oil drum in the trunk of Renju's car. While driving back to Sunfish Pocket to display the body, Ota Matsushita spotted him driving in Akihabara. Saito told Ota he was running an errand for Renju, and asked him to keep it a secret, since an idol driving without a license could damage her career. He then hung up Renju's body using a fish hook and three beer kegs as counterweights.
On Sunday morning, Iris was scheduled to record a podcast. Not wanting to draw suspicion, Saito recorded her podcast, then encountered Date in the Lemniscate lobby. Date took Saito to ABIS, where he interrogated him about his involvement in Renju's murder. During the interrogation, Saito sent a series of NILE messages to Ota, telling him he was being accused of Renju's murder. Ota swore not to tell anyone about "that thing," referring to their encounter in Akihabara the night before. Eventually, Date caught Saito using the phone under the table, and Boss encouraged Date to Psync with him for more information.
Date asked Saito about the events of his Somnium. Saito denied knowing So, and refused to elaborate on "that thing" from Ota's NILE message. Date called Ota, who asked for Iris to be brought to Matsushita Diner in exchange for information. During the drive to the diner, Saito likely messaged Ota to ask for his help escaping from the police's watch. Shortly after arriving at the diner, Ota knocked Date out with a wok and left to get the car. Saito took the opportunity to steal Mayumi Matsushita's floral kitchen knife, then left with Ota.
In the car, Saito asked Ota to stop to buy a drink. At around 10:30, they stopped in a FamiSto parking lot, and Ota left Saito alone in the car. While Ota was distracted, Saito pretended to scream for help, got in the driver's seat, covered his fingerprints with Iris's jacket sleeves, and drove away. He drove to the Sejima residence, where he asked to see So. So let him in, and eventually agreed to come with him. Saito drove them to the chemical plant, where he removed Iris's left eye and swapped bodies. After the swap, he ate Iris's removed eyeball.
After midnight on Monday, Saito (now in So's body), took So (in Iris's body) to the Okiura Fishery Cold Storage Warehouse. He set up a live stream, put on a polar bear costume, and prepared to saw Iris's body in half with an ice-cutting machine. Ota eventually tracked them down and stopped the saw, then fought Saito. Ota managed to turn on the crane and injure Saito's leg, but Saito stabbed him in the stomach with Mayumi's kitchen knife. As Date arrived, Saito fled out the back door, dropping the polar bear costume in the water.
Later that day, Date visited the Sejima residence to investigate. Saito denied having any involvement with the case, knowing Iris Sagan, or having a relationship with the Kumakuras.
On Tuesday morning, Saito got in contact with Boss. He put her to sleep, took her to the chemical plant, removed So's left eye, and swapped bodies. In Boss's body, he ate So's eyeball, shot So's body in the head, cut the body to pieces, and stuffed the pieces into a vase. He took the vase back to the Sejima residence to be discovered later.
That evening, Aiba went over the case with Date and Saito. She had found footage of Saito (as Iris) taking the knife from Mayumi, as well as Shoko Nadami's eyeball in Renju's stomach.
On Tuesday afternoon, Saito visited the cold storage warehouse. Date spoke to an inspector about the case before noticing him in the distance. Date saw that he was limping from his injured leg and called for him to stop, but he got in So's car and drove away. Around 5:00 PM, he met up with Hitomi Sagan, who wanted to speak to him about paying for Iris's brain tumor treatment. Mizuki witnessed them both around this time.
While Pewter was analyzing So's DNA, Saito used So's influence in the police to put a stop to the investigation, forcing Date off the case. He also hired several men to tie up Mizuki and leave a warning to Date to stop investigating.
Date and Mizuki came after him. So's force of bodyguards tried to stop them, but Date and Mizuki fought them all off. However, during the fight, Saito managed to kidnap Mizuki and spray her with tear gas. Date rushed into the mansion to rescue her, but Saito warned him not to move any closer, or he would kill Mizuki. Date managed to shoot him in the side, allowing Mizuki to escape. As she ran to Date, Saito shot at her, but Date shielded Mizuki and pulled them both out of the way. Saito shot at them a second time, hitting Date in his left eye. Believing Date to be dead, Saito stated that he had been "killed by his own father" and turned his gun on Mizuki. Before he could shoot her, Date regained consciousness and shot Saito in the head, killing him.
Date asked Saito what he knew about the Original Cyclops Serial Killings, but he said he had only heard about them on the news. Date then agreed to release him, as there was not enough evidence to hold him. Saito asked Date to drop him off at Marble, since he wanted to ask him about something there. During the drive, he messaged Ota and told him where he was going.
At Marble, Ota knocked Date out with a taser, and the two of them left in the Matsushita family van. In the car, Saito asked Ota to stop to buy a drink. While they stopped at a convenience store, Ota left Saito alone in the car. While Ota was distracted, Saito pretended to scream for help, got in the driver's seat, covered his fingerprints with Iris's jacket sleeves, and drove away. He drove to the Sejima residence, where he asked to see So. So let him in, and eventually agreed to come with him. Saito drove them to the chemical plant, where he removed Iris's left eye and swapped bodies. After the swap, he ate Iris's removed eyeball.
After midnight on Monday, Saito (now in So's body), took So (in Iris's body) to the cold storage warehouse. He set up a live stream, put on a polar bear costume, and prepared to saw Iris's body in half with an ice-cutting machine. Ota eventually tracked them down and stopped the saw, then fought Saito. Saito overpowered him and stabbed him with a kitchen knife. He turned the saw back on, killing Iris, then put Ota in the polar bear costume and used the ice-cutting machine on him as well.
Later on Monday, Saito got in contact with Boss. He put her to sleep, took her to the chemical plant, removed So's left eye, and swapped bodies. In Boss's body, he ate So's eyeball, shot So's body in the head, cut the body to pieces, and stuffed the pieces into a vase. He took the vase back to the Sejima residence to be discovered later. He also sent a video of the murder to Boss's PC. Saito kidnapped Hitomi Sagan and took her to Boss's house. He strapped bombs to her, prepared a livestream, then headed for the Sagan Residence.
Date arrived after 1:00 AM, where Saito and a team of officers cornered him. Saito accused Date of being the New Cyclops Killer. Date fought back by throwing a bag of flour and causing an explosion that damaged Saito's right shoulder and left leg, and knocked him unconscious. Date brought him back to ABIS to Psync with him.
After the Psync, Date realized the truth of the New Cyclops Serial Killings and questioned Saito about the murders. Date knew that Saito was not really Boss, and he had been swapping bodies with each of his victims. Saito admitted the truth, explained the details of his crimes, and explained why he wanted revenge on Date. After explaining everything, Saito demanded his body back. Pewter ran in with a laptop showing the live stream of Hitomi. Saito asked for his body in exchange for Hitomi's location, and Date reluctantly agreed to Psync.
Date and Saito successfully switched bodies with the Psync Machine. Date, now in Boss's body, demanded to know Hitomi's location. As promised, Saito told him she was at Boss's house, but moments later, the bombs detonated, killing Hitomi. Date attemted to run after Saito, but collapsed due to Boss's broken leg. Before Saito could leave, however, Aiba knocked him unconscious with a paralyzing shock.
Case of Shoko Nadami (Branch B)
On Saturday, Saito called Iris around 5:00 PM to meet him at Sunfish Pocket. However, because of Date's earlier warning to her, Iris refused. Saito thought Iris might trust him if he arrived in person, so he drove Renju's car to pick her up. However, at 6:10 PM, he got in a car accident on the highway and lost consciousness.
On Sunday, Saito woke up in the hospital after his surgery. It was successful, but Renju's organs had not completely healed. Still determined to carry out his plan, Saito escaped the hospital, rented a car, and headed for the Sagan Residence. He arrived at 2:00 AM and asked Iris to come with him to the chemical plant. She agreed, but Saito's sleeping pills had been left behind in Renju's car, so he had to hope she would not try to run. When he tried to take her inside, Iris got scared and ran away. Unable to chase her because of Renju's injuries, Saito collapsed.
On Monday, Saito woke up around noon in the chemical plant. He got a call from Pewter, who explained that #89 was en route to ABIS for questioning. Saito saw it as an opportunity to get out of Renju's body before he died, and he knew Iris would trust him as #89. He asked if it was possible to let #89 escape police custody, and Pewter agreed. Saito also told Pewter about the mercenaries he had hired using Renju's money, and left him in charge of them. Later, Saito arrived to pick #89 up after escaping from ABIS, and took him to the chemical plant. Saito talked with Rohan (in #89's body) for a while, but he knew he was running out of time. Saito put him to sleep and began the Psync. Soon after, Rohan died from Renju's injuries.
On Tuesday, Saito made a video call to Iris at 1:40 AM. He told her he wanted to see her, and Iris got excited and dropped her guard. She agreed to meet up, and Saito put her to sleep in the car, restrained her, and called Hitomi. Using a voice changer, he told her that he had Iris, and would kill her if she went to the police. He asked her to bring Date with her to the abandoned chemical plant.
Date and Hitomi arrived at the chemical plant at 9:30 PM. Date entered the back room alone and lifted the sheet Saito had placed over Renju's body. While he was distracted, Saito knocked him unconscious with a taser, restrained him to the Psync Machine, and waited for him to wake up. After Date woke up, he explained his plan: take his original body back and kill Iris and Hitomi in front of Date. He also explained what he did over the past week, along with the details of Manaka's murder. After he finished explaining, Saito put Date to sleep, removed Aiba from his eye socket, ripped out his own left eye, and began the Psync.
Saito successfully swapped bodies with Date. Back in his original body, he placed Aiba into his left eye socket, and waited for Date, under the effects of the sedative from the Psync Machine, to recall all the memories he had lost. After Date came to and Saito filled in the gaps in his memories, Date tried to attack him. Before he could, however, Saito pulled out Date's Evolver and asked if he would rather die before or after Iris and Hitomi. However, at the last second, Moma jumped through the open window and fought off Saito. He ran into another part of the factory, where he had restrained Iris, and waited for Date.
Date eventually left the back room and saw Saito holding Iris at gunpoint. While Iris tried to call for help, Saito explained his love of fireworks, and compared committing murder to watching fireworks. Before he could shoot Iris, however, Mizuki leapt in behind him and knocked him off the scaffolding with her pipe. As she continued attacking him, Saito managed to reach the Evolver and shot Mizuki in the leg. Date got into a fistfight with him and eventually knocked him into a corner of the chemical plant. Saito ran up the steps for the control room, where Hitomi was tied up.
Eventually, Date, Iris, Mizuki, and Ota found him, and ran up the steps to the scaffolding across from the control room. Saito told Date that if he dropped his weapon, he would delay Hitomi's murder. Date aimed the gun at Saito, and Saito explained that if he missed, he would kill Hitomi. Date decided to lower his weapon. However, Saito demanded that he throw the gun down, and began a sixty second countdown. As Saito finished his countdown, Date threw down the gun. Saito told him that now instead of killing only Hitomi, he would kill all five of them. Before he could pull the trigger, however, Date activated Aiba's self-destruct function. Aiba detonated in Saito's eye socket, blowing his head off.
Story (ARG timelines)
See A-set (impostor).
Saito's actions before 2019 in the ARG continuity are unknown, but it is likely that the same events occurred up until Iris began her channel, and he had taken over Shoko Nadami's body.
On March 12th, 2019, Iris Sagan disappeared on her way to the airport for her flight to San Francisco. Ota Matsushita and Kotaro Uchikoshi both began searching for her and looking into her disappearance, the former in Tokyo and the latter in San Francisco while attending Game Developers Conference. On March 20th, a video titled "rw nw prt m hrw" appeared on A-set's YouTube channel, showcasing the game's events of November 4th, 2019: Saito (presumably in So Sejima's body) wearing a polar bear costume and slicing Iris's body in half with an ice-cutting machine.
Some time between March 12th and March 20th, Saito kidnapped Iris and swapped bodies with her. Iris's fate after that point is unknown, but Saito used her body to fly to GDC by March 20th. That night, Uchikoshi claimed that he could not find "rw nw prt m hrw" online on her channel, showing Iris's apparent death, and the last upload was the video "6". Later that evening, Uchikoshi found Saito (who he believed to be Iris) roaming around the halls of the GDC's Moscone Convention Center. Saito pretended to be Iris and spent several days hanging out with Uchikoshi at the Spike Chunsoft booths at GDC, filming video and taking pictures—events that Uchikoshi later claimed never occurred, as he could not recall them.
The following week, Saito flew back to Tokyo and arrived at the Sagan Residence. Soon after, he posted a brand new video on A-set's channel, "A-set's GDC All-Access Convention Report!," where he included the photos and video footage he took at the convention. He acted as if everything was normal and no videos had been posted since "A-set Reservations Unknown" three weeks prior. Ota, concerned for Iris's wellbeing after not seeing her for weeks, visited the Sagan Residence the following day. Ota believed Saito to be the real Iris, dismissing inconsistencies in her behavior as a product of jetlag from the trip home. From then on, Saito began prepping a "big performance soon."
Visit to ABIS
Saito's Troubled Mind
Reveal and Disappearance
This section is a stub. Expansion needed.
In his original body, Saito has light brown hair and green eyes. He wears a simple outfit of a white suit jacket with a simple dark blue shirt underneath.
This section is a stub. Expansion needed.
Saito is often described in a derogatory way, being called a psychopath. The only way he feels pleasure is through other people's suffering, thus leading to his interest in murder. Even after possessing a body that lacks the original disorder that made him a serial killer, he remains homicidal and sadistic, even admitting that he desires his disorder back so he can enjoy murder as much as he did before he ended up in a body with a functional conscience. He takes great enjoyment in inflicting physical and emotional pain on people due to the rush he gets from performing the act. He is often seen laughing maniacally. Saito has a love of fireworks and often makes references to them, especially when using a gun, likening the blow of a gunshot to fireworks.
|AI: THE SOMNIUM FILES|
|Day 1: sigAI|
|Day 2: saikAI|
|Day 2: meikAI||Day 2: keitAI|
|Body Only||Body Only|
|Day 3: syokubAI||Day 3: gyoukAI|
|Day 3: rihAI||Day 3: gumAI||Day 3: kyuusAI|
|Day 4: youdAI||Day 4: jukkAI||Day 4: syuurAI|
|Day 4: jikAI||Day 4: syougAI||Day 4: kikAI||Day 4: irAI||Day 5: kenzAI|
|Body Only||Body Only||Appears||Body Only||Body Only|
|Day 5: zugAI||Day 5: seisAI||Day 5: jinnAI||Day 5: dakkAI||Day 5: jutAI|
|Mentioned||Appears||Appears||Body Only||Body Only|
|Day 5: syokuzAI||Day 5: ihAI||Day 6: kekkAI||Day 5: kokkAI|
|Ota: END||Day 6: hiAI||Annihilation: END||Iris: END||Day 6: sousAI|
|Day 6: sanpAI||Day 6: hakAI|
|Mizuki: END||Three Months Later: kassAI|
- Saito (犀人) means "rhinoceros person," and may be referring to a mythological cyclops, depicted in-game as having a horn.
- Saito is a play on the word "sight," and may also be a play on "parasite" or "psychopath."
- The Cyclops Serial Killings, often abbreviated "Saikuro" (サイクロ) in Japanese, are a combination of the killers' names: Saito + Kumakura Rohan.
- In the Famitsu Interview, it is stated that the reason Saito decided to swap with Hayato Yagyu (who was residing in Rohan Kumakura's body at the time) is due to his curiosity in the process, as well as an admiration on the strong male physique.
- It is unclear what occurred with Saito before his appearance in the Lemniscate YouTube series, and what becomes of him after his disappearance from those videos.
- In a fan-made Character Poll for AI: THE SOMNIUM FILES held on Twitter, Saito Sejima came in 14th place, tying with Ota Matsushita.