Unomaru's father was always at work and whenever he came home his mother would yell at him. One day, when Unomaru was 14, his mother murdered his father and killed herself. Unomaru saw this happen and he started laughing.
10 years before the events of the Embryo Incident, Unomaru worked for the Takamagahara Group on their attempts to create the T-System. Unomaru was present during the Wadatsumi Incident but survived due to being in the center building of the Wadatsumi Research Facility. He lost his memory of the incident but eventually regained them thanks to his meticulous notes.
5 years before the Embryo Incident, while working on an Embryo Storage, Unomaru cursed Ryouko Kagari for getting in his way and that if not for her, the world would have become perfect already. However, Unomaru said that didn't matter anymore and commanded the Embryo Storage to awaken. Seeing that her eyes were not blue, Unomaru declared her a failure and prepared to scrap her. Suddenly, the Embryo Storage spoke to him, causing Unomaru to name her Es and decide to turn her into a member of Sleipnir.
At some point he invented TOi as a test for the T-System.
Code: Embryo, Lost: Memories
After detaining a Union, Es contacted Unomaru and told him the mission was complete. Unomaru then told her he had data on a Union in the Restricted Ward and for her to go there immediately, so Es headed out.
That night, Unomaru and Mei Amanohokosaka arrived at Touya's house on the night he was attacked by Goro Joizumi. He told Hinata Himezuru to go buy tea so that he could talk to Touya uninterrupted. After making Es check if Touya had a crystal on his body, Unomaru explained that he assigned Es to protect Touya in case he got attacked again. He then took a sample of Touya's blood to test if he's a Union and left with Mei. In the car ride back, he asked Mei if she sensed the Azure from him. Upon learning that she did, although faintly, he said that things have gotten interesting and showed Mei the data he gathered on Touya, revealing to her that Touya was a Wadatsumi survivor. 
The next morning, Es met with Unomaru at the Mitsurugi Agency's headquarters. Unomaru asked her if anything strange happened with Touya and Es said he seemed like a normal human. Unomaru gave Es the mission to continue to guard Touya and told her she would be transferring into Touya's school. Unomaru tried Es to act natural around Touya's friends but Es was confused by the term friends, which annoyed him. Later, Unomaru arrived at Hakuo North Academy to talk to Touya. He told Touya that the Mitsurugi Agency bought Touya's school claiming it was a coincidence but it was actually to allow Es to transfer in easily so she could continue to guard Touya. He also explained that for some reason Touya could hear a Discover Call up to 300 meters away. Unomaru played on Touya's desire to protect people to try and convince him to use his powers to assist Es in tracking down Unions. When that failed he played on Touya's guilt over surviving the Wadatsumi Incident, telling him that his mother, Ryouko Kagari, was responsible for the incident and the Union outbreak as a result. After school ended, Unomaru called Es to tell her she would be staying at the Himezuru residence.
That evening, he had the first encounter with Akio Osafune covered up as a gas explosion. The next morning, Es contacted Unomaru to tell him about Touya collapsing and about Kuon wanting to guard Touya, which he agrees to. She then mentioned that Akio got away because of the Ten Sages, which shocked Unomaru, wondering if they were after "it" too. He then told her to continue monitoring Touya.  Later, he approached Touya and expressed his gratitude for deciding to help him and his “dedication to justice,” something Touya denied as his reason. 
A few days later, he appeared at the pool, having been the one to give Yuki Himezuru the tickets in the first place. He gave Es the order to have fun. He claimed he came to the pool, which was funded by the Mitsurugi Agency, by complete coincidence but also dragged Mei there against her will. 
Two days later, Es decided to call Unomaru and ask for maintenance. After giving her report, Unomaru said he was too busy for maintenance and told Es it was an endurance test, an order she must follow even if it killed her and that she no longer needed to contact him, since he was too busy working on the Es-N units. Unomaru stopped contacting anyone for several days until Akira Kamewari survived removing his crystal, at which point he told Es to return to the Mitsurugi Agency, claiming he had been doing important work. While performing Es's maintenance, Unomaru said how excited he was to have such a rare sample as Akira's crystal. Unomaru asked Es about the talisman on her body and wondered whether Mei actually cared for a "worthless doll" if she went out of her way to do that. Once the maintenance finished, Unomaru left, saying he had important things to do and didn't have time to play with dolls. That evening he found Touya and Kuon Glamred Stroheim outside the hospital, saying he came because something rare happened concerning Akira's condition (while also saying he forgot his name). Touya asked Unomaru about Es and, despite claiming it was confidential, he told Touya that she was a Prime Field Interference Manifestation. Touya didn't care about that, wanting to know why Unomaru abandoned Es. Unomaru claimed that it's because he was close to finishing developing the new version of her and when he becomes focused on something he can't pay attention to anything else. Touya was horrified by Unomaru's callousness towards Es, with him calling her a thing and assuming Touya was worrying more about what happens to her body once she died then about keeping her alive. When Unomaru was about to leave, Sechs, Drei and Acht suddenly appeared behind them. Touya demanded to know why Sechs turned Akira into a Union but Drei said it's because Akira wished for it. Unomaru was upset that he was being ignored and when Sechs called him foolish he asked why the Ten Sages abandoned their positions. Sechs said that to reach “zero” is completion and Unomaru said he doesn't understand. Sechs then asked Unomaru what he desired most from the world and Unomaru said he simply wanted the prosperity of all mankind and would do anything to achieve that, even controlling a god if one existed. After telling Touya to ask himself why he exists, Sechs disappeared alongside Drei and Acht. Unomaru called them rude for just showing up, lecturing people and leaving and said he had no idea what they're trying to accomplish before Touya hears a Discover Call coming from Akira's room and runs off.
After Touya unleashed the power of the Origin of the Grimoire, Unomaru was glad to have verified its existence. While looking through the Mitsurugi Agency's database he started laughing maniacally, saying he'd found Code: Embryo.  He then called Mei and told her to send Es back to the Mitsurugi Agency. Unomaru told Es that he had found the Embryo and about its power to use Phenomenon Intervention, as well as the Boundary. As Es attempted to get more information, Unomaru remembered why he called her and gave her a new mission; to capture Touya, who was a dangerous Union. Es doubted Unomaru's claim and Unomaru threatened to dispose of her if she rejected the mission. Es ultimately said yes to the mission.  After Touya and Es escaped, Mei called Unomaru, demanding to know why she lost command of the unit, but Unomaru said it was orders from the higher ups and hung up. 
That night, Unomaru went to the Himezuru residence to find Hinata, saying he came to talk to her about Touya's past. He then convinced her to follow him to the Wadatsumi Research Facility to hear about it. Unomaru explained about his desire to make all of mankind happy by taking away free will but Hinata said she didn't understand. Unomaru then told Hinata that Touya wasn't human and that she was the one who created him. Unomaru started attacking Hinata, trying to force her to remember what she did and yelling at her for ruining his plans. Hinata passed out and he decided to plug her into the T-System.  Once Touya and Es arrived, Unomaru sent an Es-N unit to confront them as he talked to them over the speaker system. Unomaru told Touya to go into an elevator and come down to him if he wanted to talk, but specified that only Touya was welcome. Unomaru called Es garbage and ranted about how much superior the Es-N units were, which angered Touya. Unomaru told the Es-N to kill Es and capture Touya so Touya and Es ran.
Touya took the elevator down to the core of the T-System where he was greeted by Unomaru and four more Es-N units. Unomaru revealed that he created eight of them, with another on the way and sent reinforcements to take care of Es. Touya said he needed to go back but Unomaru told him he locked the door behind Touya. Unomaru thanked Touya for coming to him and making things easy but Touya said he came to stop Unomaru from refining the Embryo. Unomaru asked him why he'd want to do that, saying that humanity would destroy itself within a century if left on its own. Unomaru told Touya the story about his parents and said he wanted to end pointless fights and help humanity reach its full potential. Touya said he might have had a point but it's wrong to manipulate people like that and he was afraid people would stop thinking for themselves. Unomaru then told Touya that his mother was also opposed to the T-System and during the Wadatsumi Incident, she shut down the T-System right before it was completed, causing the incident, but she managed to contain the damage to just the Restricted Ward. Angry that she stopped the T-System, Unomaru doctored documents to make it seem like Ryouko Kagari was in charge of the experiment and blame the incident on her as revenge. Touya called Unomaru insane since his mother was just trying to save people but Unomaru says Touya was the same since his Origin of the Grimoire is what caused the black wind that engulfed the Restricted Ward. Unomaru said it was time to refine the Embryo, which confused Touya since he came to stop it but Unomaru countered that refining it would be impossible without Touya. He then ordered the Es-N units to release the Grimoire and they pinned Touya to the ground with their swords. Unomaru told Touya that the Es-N's weapons were made from Mei's blood and had the power to control the flow of seithr, allowing them to forcibly control the Origin of the Grimoire.  Unomaru then revealed to Touya that Hinata was Code: Embryo, causing Touya to become enraged and start unleashing the Grimoire, which Unomaru said just saved him work. Unomaru had Touya absorb the seithr of all the Unions' crystals he'd collected and give it to the Embryo, completing the Embryo and opening the Gate of Sheol leading to the Boundary. Unomaru said all he needed to do is go to the T-System's control room and activate it in order to take control of the world. He also said he needed to hurry since leaving the Gate open for too long could kill everyone. Unomaru started going mad with power, saying he felt like he could do anything and laughing maniacally. However, Sechs suddenly appeared and stabbed Unomaru with the Sword of Destruction: Kusanagi. Sechs said that Unomaru's time had come. Unomaru ordered the Es-N units to kill Sechs but Sechs effortlessly defeated all of them. As Sechs turned his attention to the Embryo, Unomaru started stumbling forward, saying he wouldn't lose to Sechs but fell into the Boundary. 
- XBlaze Lost: Memories, Azure Main Memory 01
- XBlaze Code: Embryo, Episode 1
- XBlaze Lost: Memories, Azure Main Memory 02
- XBlaze Code: Embryo, Episode 2
- XBlaze Code: Embryo, Episode 5
- XBlaze Code: Embryo, Es & Hinata Route Episode 8
- XBlaze Lost: Memories, Azure Main Memory 04
- XBlaze Code: Embryo, Es & Hinata Route Episode 9
- XBlaze Lost: Memories, Green Sub Memory 04
- XBlaze Code: Embryo, Es Route Episode 11
- XBlaze Code: Embryo, Es Route Episode 12