- Date: "By the way, I didn't introduce myself yet. I'm Kaname Date, of the Metropolitan Police Department."
Mermaid: "You're a detective?!"
Date: "Something like that."
- —Kaname Date introducing himself to Amame
He is a special police officer known as a Psyncer for the Advanced Brain Investigation Squad at the Tokyo Metropolitan Police Department in Japan. He is investigating the Cyclops Serial Killings in an attempt to catch the perpetrator and bring an end to the killings. In the past, Date lost his left eye in an incident, and eventually had it replaced with an artificial eyeball containing an AI construct, AI-Ball.
Kaname Date is a police officer somewhere around his 30s, measuring at an average of 184 cm (when compared to Iris Sagan's canon height). His hair is a light shade of brown; it is scraggly and unkempt, with a small bun at the back and long strands of hair going down his face. His natural eye color is green, as evident by his right eye, but because of the incident in which he lost his left eye, it has been replaced by AI-Ball, his A.I. assistant, which appears as a yellow eye. This may give many characters the impression that Date has heterochromia. Aiba is capable of leaving Date's eye socket, at which point Date simply appears as his normal self with his left eyelid closed.
He presents himself with more professional and refined attire than his co-workers. He dresses with a long, black-buttoned trench coat going past his hips. He wears a matching pair of black pants bearing a front seam, topped off with black boots to finish the set. To compliment his dark appearance, he has some purple accents and a grey checkerboard pattern on the side of his coat. Underneath his coat, Date wears a purple long-sleeved turtleneck, topped off with a black vest. He also wears purple gloves on both of his hands, which the long sleeves reach, which makes Date's entire body completely covered in clothing from the neck downward, even without his trench coat on. He conceals an Exciting Voltaic Versatile Gun on his white shoulder holster, which he wears between his vest and his coat, and can be easily grabbed from within the seams of his coat.
Kaname Date appears very serious most of the time while on duty, often bearing a dry tone with others, which many have attributed to his amnesiac past, only remembering 6 years of his life. He refers to most of the people he interacts with coldly or distantly, not allowing his emotions to interrupt his work. Despite his serious presentation, he does share some compassionate moments with a few people around him. He also teases his partner Aiba often, humoring each other while performing Somnium dives, and laughing at silly mistakes that may occur.
His actual sense of humor is pretty dense, either not picking up on the flow of an actual joke in a conversation, or simply not finding the comedic mishaps of Aiba out of taste. He doesn't have any fondness for otaku-culture, seemingly confused at the concepts of maid cafes or showing disdain for Ota Matsushita's obsessive tendencies with idols, superheroes, and anime. However, he has shown various interests in small otaku-style hobbies, such as collecting brand stickers from Odoroki-man Chocolate for his collection. He is naive enough to believe that various individuals are not the culprit of his cases, despite having no evidence to back it up, but he maintains rather realistic expectations and ideas to balance them out, such as still pursuing a line of inquiry that he may personally not believe in, if only to ensure his doubts are cleared.
Even with a relatively recent memory-loss incident, he retains a handful of close friendships to those he knew before his amnesia, and even some he met afterwards. His closest friend is Aiba, his artificial companion, with whom he shares a neural link, meaning they can share the same thoughts and emotions. His boss at ABIS, Boss, has remained a close friend since before his memory loss, ensuring he could remain within the Squad as a member of the team. For a long time, he knew Renju Okiura and Shoko Nadami, who had previously been a married couple together. After his amnesia, he became (or remained) drinking buddies with Renju and was at least closely acquainted with Shoko, enough to feel upset at her death in November of 2019.
The relationship with Renju (and perhaps Shoko as well) eventually led Date to take in Mizuki Okiura as his roommate for 3 or more years, to which his relationship with her became something similar to that of a father and a daughter, caring for her and educating her (in martial arts) like his own family. Other people with whom he developed a friendship with include Mama, the owner of the Snack Bar Marble, which he frequented either with Renju for drinks or for inside criminal information from Mama herself; Reika, a hostess at the cabaret club Tief Blau, where he seems to frequent on his own; and Kagami, the forensic investigator he befriended during his investigations on the Cyclops case.
Detective Hayato Yagyu (柳生 隼, Yagyuu Hayato), formerly known by his codename Falco and currently known as Special Agent Kaname Date (伊達 鍵, Date Kaname), is the main protagonist of AI: THE SOMNIUM FILES and a character featured in the Lemniscate YouTube series.
Yagyu was a detective in the Metropolitan Police Department and an assassin for the Kumakura Family until the investigation of the Original Cyclops Serial Killings. An accident with the Prototype Psync Machine caused Yagyu to swap bodies with Saito Sejima, and he lost his memories along with his new body's left eye.
He returned to the MPD under the new identity "Kaname Date" as part of the Advanced Brain Investigation Squad. As a Psyncer, Date uses the Psync Machine to dive into the minds of suspects or persons of interest. His missing left eye was replaced with a prosthetic eye containing an advanced artificial intelligence known as AI-Ball. In the first week of November 2019, he investigated the New Cyclops Serial Killings.
“F had no parents, no siblings, and grew upon an orphanage since he was born. He suffered every abuse imaginable there. It led him to despise all the evils of the world.”
—Rohan Kumakura, as #89, talking about Falco
Hayato Yagyu was born August 3rd, 1977, and was orphaned at birth. He grew up in an orphanage, where the caretakers abused him his whole childhood. According to Rohan Kumakura, the trauma of growing up in this household gave Yagyu a vindictiveness against the “evils of the world,” seeking to pass justice on acts of crime and violence.
Yagyu pursued his ambitions by joining the Metropolitan Police Academy while he was in his 20s. Within his class of rookie police officers, he met and befriended Shizue Kuranushi. Eventually the two graduated from the academy and joined the Metropolitan Police Department, where Yagyu became a detective within Investigation HQ, while Shizue became a squad leader.
In the following years, Yagyu continued his work as a detective. One day, he pursued a criminal to the Harbor Warehouse District, a man wanted for the assault and murder of multiple women. While Yagyu held him at gunpoint, the man taunted him about his connections that would allow him to escape hospitals and return to his life of crime. Though the criminal was unarmed, Yagyu shot him repeatedly on the spot. The case eventually went to trial, and the police, fearing it would cause a scandal, fabricated evidence to have it ruled as self-defense.
Eventually, Yagyu returned to his position as a detective with no consequences. The case had been a turning point for him, and he decided he wanted to dispense justice to criminals with his own hands. He continued killing criminals he deemed unjust, all while covering them up and continuing his detective work. He killed at least 17 more criminals before he was eventually caught by the Kumakuras.
One day in the early 2010s, Yagyu targeted a top executive of the Kumakura Family, a man Rohan referred to as “X.” X, along with other Kumakura members, was responsible for defrauding elderly folk of their insurance policies and killing them, starting as early as the late 90s. The current chairman of the Kumakuras, Rohan Kumakura, unhappy that one of his men had been killed, ordered some of his men to kidnap Yagyu. He was taken to the Kabasaki Chemical Plant at night, where Rohan, along with Dokuta Yogano and Chinpei Wagai, restrained him in a room at the back of the building. Rohan told Yagyu he was impressed by Yagyu's clean track record and offered him a position as an assassin for the Kumakuras, while making it clear that refusal would result in death. With no other option, Yagyu accepted. Rohan gave him the codename “Falco.”
Yagyu continued with his regular detective work by day and worked for the Kumakuras by night. He killed numerous targets throughout Tokyo, and, according to Rohan, “[it] didn’t take long to destroy his heart completely.” He continued with his work until late 2013.
Meeting the Sagans
In August or September of 2013, Falco went after a target in the Minato District. However, he missed his mark, and his target retaliated by shooting back at him. He escaped with a bullet wound to the stomach and ran until he finally collapsed against the side of the nearby Ikume Shrine. He was bleeding out and believed he was about to die when Hitomi Sagan noticed him. She noticed his wound and reached for her phone, but Falco heard the footsteps of the men chasing him nearby, so he grabbed her and kissed her to keep quiet. He let her go as soon as the men left the area and told her not to call an ambulance. Hitomi instead took him to a mob doctor, Dokuta Yogano, who was able to give him medical attention.
From then on, Falco and Hitomi began meeting in secret, becoming close together. As Rohan explained, Falco would visit Hitomi outside of work and hear her speak, which would ease his heart, slowly becoming his former self before he was hardened by his work. As the holidays approached, the pair visited a haunted house in an amusement park, which Hitomi recounts as the date where Falco was frightened by a zombie and clutched Hitomi’s arm in fear. Their second kiss occurred one night, when Falco and Hitomi drove around the city, then stopped at the Harbor Warehouse District and kissed. It is implied that Hitomi told Falco about her past that night, including her deceased friend Manaka Iwai.
Hitomi eventually introduced Falco to her soon-to-be 12-year-old daughter, Iris Sagan, who immediately took a shine to Falco and gave him the nickname “Uncle.” The three of them spent their days together, visiting the beach, the river, the zoo, the amusement park, barbecues, and more. Falco would occasionally take Iris to Ikume Shrine, where they would play hand games and talk about Egyptian mythology.
One day at the Sagan Residence, Falco decided to make okonomiyaki using a hot plate, and as he tried to flip one in the air, it landed on Hitomi’s head. Iris started laughing, so Hitomi grabbed more okonomiyaki and put one on top of both Falco and Iris’s heads, adding bonito flakes, mayonnaise, and sauce. From there, a food fight broke out between the three of them, as they threw eggs and flour. They all laughed after it was over and the room was a mess. Iris later decided to draw the “Okonomiyaki War."
The Cyclops Serial Killings
In October of that year, the bodies of four young women were found in the Akikawa Valley, their right eyes missing and in various stages of decomposition. The case was named the “Cyclops Serial Killings,” and Detective Yagyu was placed in the investigation of the crime. Outside of work, Yagyu would spend his days as Falco, either the assassin working for the Kumakuras or as Hitomi’s boyfriend. One day in November, Falco and Iris played ratty cake at Ikume Shrine. After Iris won, Falco suggested the stage name “A-set” to Iris and explained its connection to Egyptian and Greek mythology. Iris suggested that he and Hitomi should marry, so that “Uncle” could become “Dad.” When Falco visited Hitomi later, she showed off Iris’s drawing of the Okonomiyaki War, and he proposed to her. Hitomi was initially shocked, but eventually she accepted, and Falco resolved to protect the Sagan family.
Falco approached Rohan Kumakura, asking to leave his position as an assassin and go clean. Rohan agreed because of how much he had done over the years, but assigned him one final job before he could leave: kill Hitomi and Iris Sagan within the next few days. Knowing that other assassins would target them if he refused, but unwilling to kill his fiancée and her daughter, Yagyu went to the Police Headquarters and met up with Shizue, who had been appointed the squad leader of the recently established team ABIS. Yagyu confessed all his past crimes to Shizue, and explained his present predicament, and she agreed to help him. She proposed a plan using ABIS’s Psync Machine, which was normally only meant for diving into a subject’s subconscious mind, but was secretly capable of swapping bodies between the user and the subject. The plan was to bring Rohan to HQ, have Yagyu swap bodies with him, and use Rohan’s body to order the Kumakura family to leave the Sagans alone. Yagyu accepted, willing to use the plan as a way to discard his life as Falco. His only regret was that he would never be able to show his face to Iris and Hitomi again.
Within the next few days, Shizue managed to bring in Rohan Kumakura under false charges and temporarily hold him at HQ. Then, she put Rohan to sleep and brought him to the Psync Room, and explained to Pewter that Rohan and Yagyu were about to swap bodies. In Rohan’s Somnium, Yagyu witnessed all four murders of the Cyclops Serial Killings, and saw that the culprits were Rohan Kumakura and Saito Sejima. After the Psync ended, Yagyu awoke in Rohan’s body. Shizue and Pewter confirmed that they had witnessed the events of the Somnium as well and discussed interrogating Rohan. However, when they turned around to speak to him, they realized that Rohan (now in Yagyu's body) had gone missing. A police officer confirmed that he had shown "Yagyu" the exit when he asked to leave.
Yagyu knew that Rohan was headed to the Sagan Residence to finish the assassination himself. He rushed to drive after him, along with Shizue and an SAT squad. Yagyu reached the house first to see Rohan pointing a gun at Hitomi. Yagyu raised his gun at Rohan, but Hitomi, believing she was protecting her fiancé, leapt in between them. Yagyu shot three times, leaving Hitomi with wounds in her shoulder and side, and Rohan unharmed. As she lay unconscious, bleeding out, Rohan raised his gun to fire back at Yagyu, but Shizue and the SAT entered to surround Rohan and arrest him. Hitomi was taken to Central Hospital, where Yagyu stayed at her side after her surgery, which rendered her left arm completely unusable. Feeling guilty for injuring her and knowing he could no longer show himself to her, Yagyu left his life with her behind.
That same night, Yagyu went to the Kumakura Office as “Rohan,” where he announced that he had called off the hit order on Hitomi Sagan and her daughter. Later, Yagyu met up with Shizue, who encouraged him to speak with Saito Sejima to investigate the Cyclops Serial Killings. He went to the Sejima Residence as Rohan and asked to meet with Saito. Saito met him in the garden, where he confessed to all the murders and laid out the details of his collaboration with Rohan. However, Saito quickly figured out that Yagyu was not actually Rohan and had him surrounded by his bodyguards. Saito and his men took Yagyu to the Abandoned Chemical Plant, where they tortured Yagyu and then used a truth serum. Under its influence, Yagyu revealed the secret of the Psync Machine and the location of the prototype being developed in Chiba. Curious to see it for himself, Saito ordered the prototype brought to him and promised to pay whatever it cost. A few days later, Saito's bodyguards successfully stole the machine and set it up in the chemical plant.
Saito decided to Psync with Yagyu and swap into Rohan’s body. He removed Rohan's eye and his own, then sat in the Psync chair and began the process. However, an error occurred, forcibly disconnecting the pair during the Psync. The body swap was successful, but the memory transfer was not, so Yagyu awoke first in Saito's body with no memories. He tore off the Psync Gear and saw that he was surrounded by bodyguards, so he jumped through the window to escape and ran.
Yagyu's memories immediately following the incident were hazy, but he managed to get from the Kabasaki District all the way to the Shinjuku District, where he found himself wandering aimlessly around Golden Yokocho. There, Shizue found him, believing him to be Saito Sejima. After speaking to him, she quickly realized he was Yagyu with amnesia, and took him in, calling herself his “Boss.” Some time later, and, with the help of the MPD and So Sejima, Boss was able to make a new family registry for him. She gave him the name Kaname Date and formally had him join the ABIS team as their new Psyncer.
New Name and ABIS Life
In November 2014, Pewter called Date into the Psync Room to introduce him to Aiba (full name AI-Ball), an artificial intelligence housed in an artificial eye to replace his missing left eye. Pewter explained that Aiba would be his partner going forward. Aiba could link to his mind by a neural connection, allowing them to communicate and use's Aiba's special vision modes. Date and Aiba began working as a pair: Date would conduct real-world investigations with the help of Aiba's x-ray, thermo, and night vision modes, while Aiba would act as his avatar in Somnium investigations. Unbeknownst to him, she also regularly supplied oxytocin, the chemical Saito's brain was unable to produce on its own.
Date eventually became acquainted with Renju Okiura and Shoko Nadami. Date and Renju frequented the bar Marble together, where they would talk over drinks. On one occasion, Renju asked Date if he had ever seen a dead body. When Date turned the question on him, he talked about his involvement with the Kumakuras high school. He explained that initially worked as part of a phone fraud scam but eventually befriended the higher-ups and accompanied them on jobs. They met with wealthy elderly people, convinced them to adopt the yakuza members, then drowned them to claim their money as inheritance. When Renju asked Date if he would arrest him, Date told him he had no part in the murders themselves, but Renju's guilt remained.
While Date was drinking with Shoko one night at Marble, she complained to Date about parenting her daughter Mizuki and told him she was sometimes forced to hit her. Date scolded her for abusing her child and decided to talk to Renju about the situation. Renju explained that Shoko refused counseling, and it was hard to separate Mizuki from her. He was unable to take care of her himself because he was too busy running his company. Date told him that both of them were terrible parents. Renju later suggested that Date take in Mizuki.
In 2015, Renju and Shoko were divorced, and Date took her in at his apartment. As part of Date's agreement with Renju, Renju was still her legal guardian, and would occasionally check up on her and spend time together. Mizuki and Date grew closer over time—for her birthday one year, Date gave her a plush Adorabbit doll as a gift. She initially called it ugly and dismissed it, but grew to love the doll.
In 2016, Mizuki developed an interest in collecting Odoroki-man Chocolate stickers. Date joined her in collecting the stickers, and even continued collecting them after she lost interest.
In 2017, Mizuki came home from being bullied at school. Date offered to train her in martial arts, and took her to Ikume Shrine. There, he talked to her about mental preparation in a fight, and asked her to throw a punch to gauge her strength. Mizuki displayed incredible physical power, though she was unaware of just how strong she was. Date continued to train her, and after some time, Mizuki was able to knock a tree at the shrine over with her strength.
New Cyclops Killings/Shoko's Murder
This section is a stub. Expansion needed.
On November 1st, 2019, Date was called to Bloom Park to investigate a body found there. Date recognized the victim as Shoko Nadami, tied to the merry-go-round and missing her left eye. Boss, at the scene, noted that it seemed like a copycat crime similar to the murders six years ago, but would not give Date any further information about it. Once Date and Aiba finished examining the body, they heard a noise from the central column of the merry-go-round. Date used his Evolver to shoot the column's lock open, and discovered Mizuki inside, holding a bloody ice pick.
Date took Mizuki to Central Hospital, and fell asleep while watching over her. He had a strange dream in which Aiba appeared to him in humanoid form for the first time. Aiba explained that there were several mental locks in his dream, and they would need to unlock them to progress. As they did so, a number of pieces from Date's lost memories appeared, including Hitomi Sagan and the Sagan Residence, though Date did not recognize them. Just before he woke up, Date witnessed Hitomi bleeding out on the floor.
The next morning, Date went over the investigation with Boss, who explained that Mizuki was unable to speak as a result of her trauma. As Date and Boss discussed possible leads, Aiba announced her discovery of the person who reported the crime: Ota Matsushita. Date and Aiba headed for Matsushita Diner, where they met Mayumi Matsushita and determined that Ota was not home, and was likely at Lemniscate instead. At Lemniscate, Date questioned Ota about the crime, and learned that he was a friend of Mizuki's who accompanied her Bloom Park after she got a NILE message telling her to come to the merry-go-round. Ota panicked and ran away, leaving Mizuki behind.
|AI: THE SOMNIUM FILES|
|Day 1: sigAI||Day 2: saikAI||Day 2: meikAI||Day 3: syokubAI||Day 3: rihAI|
|Day 4: youdAI||Day 4: jikAI||Day 5: zugAI||Day 5: syokuzAI||Day 4: syougAI|
|Day 5: seisAI||Day 6: hiAI||Day 6: sanpAI||Day 3: gumAI||Day 4: jukkAI|
|Day 4: kikAI||Day 5: jinnAI||Day 5: ihAI||Day 2: keitAI||Day 3: gyoukAI|
|Day 3: kyuusAI||Day 4: syuurAI||Day 4: irAI||Day 5: dakkAI||Day 6: kekkAI|
|Day 5: kenzAI||Day 5: jutAI||Day 5: kokkAI||Day 6: sousAI||Day 6: hakAI|
|MaiN: 1||MaiN: 2||MOUNTaiN||CHaiN|
- The term Generalized Amnesia was a keyword featured in the announcement trailer for AI: THE SOMNIUM FILES, floating in the background at the beginning. This term applies to Kaname Date's amnesia from six years past.
- Kotaro Uchikoshi wrote Kaname Date as an amnesiac as a convenient plot device, as he feels it helps immerse the player in the protagonist's shoes. As such, the amount of information that both the player and the amnesiac protagonist know are the same, and it serves as a means of having the other characters explain aspects of this world to both of them in an organic way.
- A cut plotline for the game involved Date being in some romantic relationship with Hitomi Sagan, the mother of Iris Sagan and the original planned main heroine of the story. However, once the story was rewritten and Iris was made the main heroine instead, Hitomi was pushed more to the sidelines as the romance plotline was subdued.
- Kaname Date is Kotaro Uchikoshi's favorite character in the game.
- As the protagonist of AI: THE SOMNIUM FILES, Date has appeared in every single chapter within the game. In fact, he is the only character to appear in every single chapter in the game, as Aiba never appears in Day 6: –hiAI– and PSYNCIN' IN THE CHaiN, and only appears as an eyeball within Date's eye socket in Day 6 –kekkAI– and PSYNCIN' IN THE CAPTaiN.
- According to the localization coordinator/editor/producer, Alex Flagg, on Discord, there is a secret hidden in the cover art for AI: THE SOMNIUM FILES. If you look at all the space that the characters and objects take up in the image, it makes the shape of a keyhole. Kaname Date stands in the center of the image, and, as explained in Day 2: Saturday –saikAI–, the kanji used for Kaname, 鍵 (Kagi), translates to "Key." As such, the mystery of the game is a keyhole, and Kaname Date is the "Key" that fits inside.
- In a fan-made Character Poll for AI: THE SOMNIUM FILES held on Twitter, Kaname Date came in 3rd place, while his past identity as "Falco" came in 8th place.