Code: Embryo, Lost: Memories
The night Touya Kagari would become involved in the Union conflict, Es and Mei battled a Union whose Drive let him control objects from a distance. Mei warned Es not to charge in blindly but Es ignored her, getting injured in the process. However, Es claimed the damage was minimal and defeated the Union. Mei angrily demanded to know why Es put herself at risk, but Es said that her safety was irrelevant if it meant completing the mission. A frustrated Mei left and told Es to report to the Mitsurugi Agency.
Later that night, Mei arrived alongside Souichiro Unomaru at Touya's house. Mei stared at Touya closely and yelled at him to shut up when he complained. In the car ride away, Mei told Unomaru that she sensed a faint presence of the Azure from Touya. After she complained about their “cooperative relationship” being one for Unomaru's convenience, he gave her all the data he had gathered on Touya. She was shocked to find out that he was a Wadatsumi survivor. 
The next day after school, she approached Touya after hearing he would cooperate with the Mitsurugi Agency. She constantly insulted him while explaining that Unomaru begged her to back up Touya if he decided to join. She then placed the Goofball Proximity Surveyor on him. After explaining that it would let her see whatever he sees and warning him to avoid the Magic Guild, Mei left. 
The next morning, Touya saw Mei on the phone where she was angrily saying she refused to work alongside anyone from the Magic Guild. Mei claimed that she would protect Touya so he shouldn't rely on someone from the Magic Guild and she wouldn't lose. 
That night, she was investigating a Union-related incident when Touya suddenly approached her, causing her to hit him. She got very mad at his continuous apologies and him not seeing her as a noble shrine maiden. Mei decided that he could tag along but told him to keep quiet. She studied Akio Osafune's body and concluded that it was the work of Ripper. After finding the night watchman's body, Touya sensed a Union and warned Es and Mei. Es deflected a thrown knife, but Ripper threw a smoke bomb at them. Mei fired a Shikigami Raven at him and he appeared behind Touya but Es knocked him away. Mei told Es to pursue while she protected Touya, with the two following behind. Learning that Avenge had entered the fray, Mei told Touya to hurry up but he said he couldn't go any faster so Mei just grabbed him and used her powers to fly while carrying him there. When they arrived, Ripper fled and Avenge told them to leave Ripper to him - calling Mei a little girl, much to her anger. She reported to Unomaru about Avenge and told Es to take Touya home. 
Two days later, Unomaru forced her to go to the pool with everyone against her will. She stayed in the kid pool, claiming she could swim but just didn't want to in order to hide her inability to swim. Afterwards, Kuon Glamred Stroheim attempted to speak with her, but Mei quickly became hostile, calling her “witch” and insulting her for being part of the Magic Guild.
On the school roof during lunch Mei overheard Touya, Es and Hinata Himezuru talking and complained about going to school with other people, just wanting to eat her lunch in peace. She then overheard Touya and Kuon talking about anime and accused Kuon of being a fangirl while acting elitist about her anime tastes at the same time. When she overheard that Es watches Sunday morning kids' cartoons, Mei accidentally revealed herself before angrily saying she needed to speak with Es. 
In the bath, Mei sensed the confrontation between Touya, Es, Kuon and Sechs and worried about it. She later called Touya to learn what happened, but got mad when he said he was with Kuon, telling him how the Magic Guild ruined her clan.
Two days later, she approached Touya on the school roof and demanded to know what happened the day before so he told her about the confrontation with Acht. Mei complained about getting even more work to do, wondering why one of the Ten Sages was out in the open. She started an argument with Kuon, revealing that she knew about Elise von Klagen staying with Touya thanks to the G.P.S. Once Kuon left, she told Touya what she initially came to him for; that three more bodies had been found and someone who looked like Akira Kamewari was spotted nearby, although Mei doubted he was responsible. She promised to send out a familiar to search for him. 
That night, she arrives at the Himezuru residence to find the newly-Union Akira attacking Touya and Es. She apologized to Touya, saying that Akira was classified as a Union and she had to detain him. Akira briefly regained his sanity and ran off. Mei noted that he had already progressed through a couple of phases and was upset that she couldn't get through to Unomaru. Elise introduced herself to Mei and Mei was taken aback by how polite she was. Mei performed first aid on Touya, Hinata and Es but said Es was in bad shape. Mei used a special charm specifically for her, which she hoped would repair most of the damage even if it couldn't fully heal her. Mei explained to Kuon that most of the damage was from deterioration since Es normally returned to the Mitsurugi Agency headquarters every two days for treatment, but hadn't gone in a while. While Mei did not know what Es was, she speculated that she was a living doll. Kuon was shocked to find out that a Homunculus existed but thanked Mei for being there to help, saying there's nothing sadder than losing a family member. Mei, remembering that Kuon just lost her father, confided in her that she also lost her mother, Sui Amanohokosaka, during the Wadatsumi Incident and could understand her pain. Mei then discussed with Kuon and Elise how unnatural it was for Akira to already be in phase three and what the Ten Sages were planning, specifically to push Touya over the edge. Mei told them that she heard a strange Discover Call from Touya. She confirmed that he wasn't a Union but was worried about the Discover Call's meaning.
The next day, she received word that Es would be taking a three-hour break and headed to the Himezuru residence to watch Touya. She caught him trying to sneak out but decided to accompany Touya somewhere as long as it's close by and he chose Maha Raja. Upon meeting Ringo Akagi, Mei initially assumed her to be Zwei of the Ten Sages, but concluded there's no way she'd be working at a curry restaurant. Ringo said she had no idea what Mei was talking about. She then told Touya about the history of her clan; that they had been guarding the “Legendary Lands” since before recorded history but when the Magic Guild brought the clan to ruin, they sold the Legendary Lands to the Takamagahara Organization for a lot of money. After the Wadatsumi Incident, Takamagahara disbanded and the Mitsurugi Agency came in to support the Amanohokosaka clan in exchange for using the shrine maiden's powers, which was why Mei had to listen to Unomaru. 
The next day inside the Shin Yokozaki University Hospital, Mei ran into Yuki Himezuru after visiting her father. Mei asked Yuki to explain the situation to Touya when he arrived. Mei took Yuki to the roof and told her she could get in touch with Avenge for her. Mei promised to tell Yuki what she knew, but warned her that it involved the incident 13 years ago. Mei told Yuki the story behind her parents' murder, how Avenge saved her and that Ripper survived, but it was covered up since he was a Union. Mei then asked about Hinata, wanting to know who she was since Yuki was an only child. However, Yuki said that Hinata was absolutely her younger sister, regardless of blood connections. She then told Mei the story of how she met Hinata. Mei warned Yuki that she shouldn't meet with Avenge but Yuki said she had to in order to learn about Hinata's past. Mei relented and said she'd get in touch with him for her. 
That evening, she received word that Hinata had been kidnapped by Ripper and went to get Es from the Mitsurugi Agency's headquarters, telling her they needed to hurry. In the car, the two discussed what they knew about Ripper. Mei found them on a roof in the Restricted Ward and they headed over. They saw Hinata falling and Mei used her magic to help Es catch Hinata. While Touya was going berserk after unleashing the power of the Origin of the Grimoire, she healed an injured Kuon with her charms and showed Touya that Es saved Hinata, calming him down.  Mei tries to get Touya to wake up and told Es to take Hinata back to the Himezuru residence. She was angry that the G.P.S. ended up being totally useless. She told Kuon that Touya unleashed the power of the Black Beast. Drei and Sechs then arrived and Sechs told them that they needed the power of the Black Beast to destroy the Embryo. Drei told them that Unomaru was planning on using the Embryo to control the minds of everyone in the world. He warned Kuon and Mei not to get in their way or they would return everything to seithr and that all that mattered was the future Sechs was trying to create. Sechs and Drei then disappeared. Once Touya woke up, Mei promised to tell him and Kuon everything she knew but suggested they return to the Himezuru residence since it was too dangerous where they were.
Back at the Himezuru residence, Mei told Touya and Kuon and about the Gate of Sheol underneath the Wadatsumi Research Facility, about the Amanohokosaka's history guarding the Gate and that the first Azure Shrine Maiden stopped the Black Beast from emerging by luring it back into the Gate and sealing both of them inside it. Touya had doubts that Unomaru was planning what the Ten Sages said he was, which angered Kuon. Mei told Kuon not to put too much faith in the Ten Sages words and Kuon countered that she was saying they couldn't trust Mei because she's part of the Mitsurugi Agency. Mei said her family was basically being held hostage and Kuon wouldn't be able to act if she was in the same situation. Kuon said she came fully prepared to kill her own brother, but Mei didn't believe that. Mei said she had plans to eventually reclaim Wadatsumi, which Kuon didn't accept. Kuon then left, saying she's going to speak to Sechs one more time and that she'd probably never return to the Himezuru residence. Mei told Touya that she would be guarding Touya from then on in case the Grimoire went berserk again, but he was worried about Kuon and ran off. Mei got angry and said it's not her problem anymore. After Es came out and managed to calm her down, Mei explained to Es about what happened. Es then convinced Mei that Kuon actually did trust Mei, surprising her that Es was acting as the voice of reason. She then received a call from Unomaru, who had her tell Es to return to the Mitsurugi Agency. Mei warned Es about the Ten Sages, saying Unomaru was planning to control the minds of all mankind and said Es would have to choose a side eventually. 
Touya was classified as a high-risk Union that needed to be taken in and Mei was put in charge of the unit searching for him. She found him and Es together. Touya told her about Es's promise to kill him and Es said she knew she would die for betraying the Mitsurugi Agency, which caused Mei to quit the Agency in frustration, saying the two needed to care about their own lives more and consider how those close to them would feel if they died. Mei told Touya she would find Kuon so he should focus on escaping. Mei covered for them with a smoke bomb and they escaped underground. 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. Mei knew he's lying but was glad she could move more freely and prepared to meet up with Touya and Es. 
At some point she encountered Avenge and asked him to “go save that idiot.” She then met up with Touya and Es as they emerged from the sewers, saying she still hadn't found Kuon. Mei yelled at them for smelling and said she had a spare set of clothes for Es. Es thanked Mei, which embarrassed her. Mei told Touya to go home and get a change of clothes and when Touya asked if he would be safe there, she told him that Elise sent out a false lead that Touya was on a bullet train away from Shin Yokozaki City. Touya wanted to tell Mei about the T-System and the Ten Sages but Mei revealed she had Avenge put a wiretap on him and already knew about it. Touya, Es and Mei decided to return to the Himezuru residence and were greeted by Hinata. Mei asked Hinata if anything out of the ordinary happened but Hinata said she'd been sleeping until recently. Mei then asked her if Kuon returned and Hinata said she was upstairs. Hinata then realized she promised Kuon not to tell Mei about her return and begged Mei to pretend she didn't hear but Mei refused. Hinata was afraid that the two would start fighting but Es said it's okay because Mei and Kuon were friends, which took Mei aback. Mei went upstairs and met with Touya, telling him about Kuon while insulting her. Kuon told Touya and Mei to meet her downstairs since she had important information from Elise. Hinata offered them tea and Mei said how good it is, but Kuon got upset when Mei called it “cheap.” After Hinata left, Kuon read a letter from Elise that contained her findings about the Wadatsumi Incident. She discovered that Unomaru was a survivor of the incident and that he was not working to treat the Unions he captured, but rather to gather their crystals so he can refine the Embryo. She also found that TOi was powered by the T-System and was created to be a high-level information control system. Learning of Unomaru's corruptions, Mei planned to take him down so that the Mitsurugi Agency would give her control of the anti-Union activities in Shin Yokozaki City. They figured out that Unomaru was likely at the Wadatsumi Research Facility attempting to complete the T-System. Mei said Touya should stay behind because of the Grimoire and because it's too dangerous but Touya insisted he had something he needed to ask Unomaru. Kuon said they should bring Touya along and promised to kill him if he lost control so Mei agreed, but said she'd send him home if things got too dangerous. They then discussed that they needed to deal with the Ten Sages, Mei revealing that Avenge told her that he killed Drei. Mei theorized that the Origin of the Grimoire was the only thing that could destroy the Embryo and the Ten Sages had been trying to cause Touya to activate it for that reason. Mei asked if they had anything they needed to do before they headed out and Es asked for pudding so Mei begrudgingly said they'd wait until Hinata returned. After Touya got off the phone with Yuki, he told Kuon and Mei that Akira was going to be all right. Kuon was relieved but Mei said she found his ability to survive gross like an insect. Just as Mei complained about Hinata taking a long time to get back, she arrived with pudding. 
Arriving at the Restricted Ward, Mei found it odd that there was no one there. Es didn't detect any human presence inside and said if they were going to go inside they should do it then. Inside, Touya recalled how he first met Es. This caused Kuon and Mei to get in another fight, with Mei saying she couldn't believe she was working alongside someone from the Magic Guild. Kuon promised that she would force the Magic Guild to change its ways once she got back to Ishana but Mei must reclaim Wadatsumi in exchange. Mei accepted and they approached the wall around the Wadatsumi Research Facility. They were suddenly attacked by Acht's Ice magic. Es deflected all of the attacks and Acht remarked that she hoped to kill at least one of them with that attack. Acht said she had no idea where Sechs was and was no longer involved with him; she just wanted to go crazy. Acht said that they must defeat her in order to go on. She told Touya to go away since she didn't want to deal with him, but then said she's just kidding and attempted to kill him. However, Es protected him. Acht called Touya pathetic for always having others protect him. She then attacked him again but was intercepted by Mei, who told Touya to go home and he ran off. As Kuon, Es and Mei discussed what to do with Touya, Acht attacked again but got blocked by Kuon's Fire magic. Kuon told Es to go with Touya and leave Acht to her and Mei. Kuon then created a large explosion that blinded Acht, allowing Es to get past her. Mei thought Kuon was crazy, since they couldn't hurt Acht thanks to her Drive. Kuon planned to use the Sealed Spear: Izayoi, but Mei told her not to use it except as a last resort and that the two of them would defeat Acht together. Acht overwhelmed Kuon with her Ice magic, claiming she could teach Kuon a few things. Mei tried to attack with Lightning magic but got blocked as well. Kuon and Mei then both fired at Acht simultaneously, forcing her to activate her Drive to negate their attacks. As a “prize” for forcing her to use her Drive, Acht told them more about the Embryo; that the Embryo already existed in an incomplete state that both existed and didn't exist. Acht asked Mei how to destroy something like that and Mei said with the Origin of the Grimoire, but Acht said that was wrong. Acht then told her that they needed to first complete the Embryo and only the Grimoire could refine it. Kuon wondered if Sechs learned all that from the crystal, but Acht said story time was over and renewed her attack. Mei said they were in trouble if Touya and Es decided to go on ahead of them so Kuon said she had no choice but to use the Izayoi. Mei responded that she couldn't afford to let Kuon use it and had a secret weapon, the Goofball Proximity Surveyor. Mei then attacked Acht again but snuck in the G.P.S. in the confusion, negating Acht's Drive and giving Kuon the opportunity to unleash her full power against Acht. However, it wasn't enough to put Acht down, but it did cause her crystal to progress a phase. Acht retaliated by launching a large iceberg at the two, which Kuon barely managed to destroy. At that point, Acht had reached phase six and devolved to the point where she was screaming about how they were enemies who she had to kill, creating another giant iceberg. Mei told Kuon that she needed to stop firing such large spells or she'd kill herself. Kuon said she'd never be able to live with herself if she ran. She also said she didn't believe that Acht abandoned Sechs and she was doing this out of loyalty. Kuon felt she had to respect her resolve. Kuon and Mei put all of their power into one combined spell, which pushed Acht's crystal over the edge. In her last moments, Acht asked if Sechs was there and tried to tell him she loved him before disappearing into seithr, leaving behind only her crystal. Kuon and Mei then went off to find Touya and Es. 
Kuon and Mei arrived to back Es up, who was fighting three Es-N units. Es told them that the Es-N units had their combat data and could predict their moves as well as that Touya went on ahead. Mei and Kuon said that's bad since the Grimoire was needed to refine the Embryo. They then told Es to go on ahead and leave the Es-N units to them. During the battle, they felt an earthquake and realized the refinement must have started. The Es-N units continued their assault and Kuon said they'd have to leave everything to Es.
Kuon and Mei managed to defeat the Es-N units and reached the core of the T-System, where they saved Es and Touya from Sechs, but were quickly defeated by him.
One month after the Embryo incident, Touya, Kuon and Mei were chasing a Union and Touya could tell they were in phase four based just on their Discover Call. They found him and noticed he was acting unnatural and his clothes were damaged. Not wanting to prolong the fight since they're not in the Restricted Ward, Touya activated XBlaze. Touya asked Mei if she could use a spell to restrict the Union's movement since he didn't want to hurt him. Together the three managed to subdue the Union. Mei said she's glad she had Touya and Kuon's help and Kuon realized that it meant Mei was understaffed. Mei then told them that she was reprogramming the last Es-N unit to work for them, but was having trouble switching its power source from crystals to electricity. Mei said that Es-N would probably be less efficient like that, but was sure she could compensate with her magic. Kuon made fun of Mei's style for thinking a robot familiar was cool and the two got into an argument. Touya tried to break it up, but the two insisted they were having a normal conversation.
The next day at the Himezuru residence, Hinata offered Mei some tea. Mei said she didn't stop by for tea, but Kuon pointed out the box she had. Mei said it's a gift she just happened to pick up and Hinata said it's fine for Mei to visit whenever she wanted. As Kuon called Mei adorable for her behavior, Touya came downstairs. Mei said she came to say goodbye since Kuon was returning to Ishana the next day. Kuon said that Mei shouldn't have come if she was busy but Mei claimed it was important, which Kuon found endearing. Touya said he wanted to talk to them in private. Touya said it's about his lack of memories from before the Wadatsumi Incident and why he was at the Wadatsumi Research Facility in the first place. Mei realized that it was suspicious that Unomaru had so much information on Touya from the very beginning. Touya begged the two of them to help him find out more about his past, which the two readily agreed to. Mei said she owed Touya a favor for helping her with her work, since his promise to help the Mitsurugi Agency ended with Unomaru's death. Kuon said she'd have Elise look into Touya's past, since she's good at uncovering information. Mei added that she could get in touch with Avenge to ask him about it since he was one of the few people who knew about Takamagahara. As Touya thanked them, Kuon and Mei note that Touya had changed since they first met since he no longer just said “sorry” to everything. Hinata arrived, agreeing with them. Touya asked if she heard the whole conversation, but Hinata said she was making tea. Hinata brought out the sweets Mei gave her and revealed that she knew Mei actually went to another town just to get them, much to Mei's embarrassment. 
10 days later, Ringo was at the Himezuru residence and tried Hinata's curry, praising her skill. Touya and Mei found it strange that Hinata was able to have a normal conversation with Ringo. Mei said the curry looked good but Touya was sick of it, wondering how long Ringo planned to stay at their house. Mei updated Touya on the progress of his request; that she had a found a journal kept by Unomaru but she hadn't been able to open it yet. She also told him that the Mitsurugi Agency operated internationally and that the scope of it was far beyond what they expected. Touya then received a phone call from Kuon, but it turned out to be Elise. Kuon took the phone from Elise, saying she was embarrassing. Ringo interrupted, saying she would leave not that she'd stolen Hinata's recipe, which relieved Touya. Ringo said she didn't expect to see Touya any time soon and left. Kuon was surprised to find Zwei at the Himezuru residence but Touya had no idea what she was talking about. Kuon also gave Touya an update; saying she found out how the Origin of the Grimoire ended up in Wadatsumi. 10 years ago, the Magic Guild and Takamagahara cooperated to open the gate to the Boundary. Takamagahara wanted the infinite energy source of seithr while the Magic Guild wanted to find the “Roots of the Azure.” The Magic Guild had members of the Ten Sages try to force open the gate and they were lost in the Wadatsumi Incident. Elise told Kuon they needed to get back to their room since the dorm manager was making her rounds so Kuon hung up in a hurry. Mei said that, while they had learned some new information, if they wanted to get to the truth they needed to open Unomaru's journal. Touya asked to visit Unomaru's office, even if it was pointless. Mei agreed, saying he might find something with his main character-like personality. Mei then gave Touya the key card to Unomaru's office. Hinata called that the curry was ready, but Touya was sick of it after having eaten it for 10 days.
Another day, Mei called Touya back to Unomaru's office, saying she managed to decipher quite a bit of Unomaru's journal. First, Mei explained that, despite everyone who survived the Wadatsumi Incident losing their memories, Unomaru regained his quickly thanks to his journal. Mei said that despite how difficult Unomarus' cipher was, she managed to learn about most of Touya's past. Touya thanked her but Mei said she hadn't said she would tell him anything. Mei told Touya to promise he'd always be Touya Kagari, no matter what he learned. Touya promised to do so. Mei explained how the original Touya died and the current Touya was the Origin of the Grimoire transformed into a clone of him. Touya freaked out, blaming himself for the Black Typhoon that killed 3000 people. Mei said that it was likely that the transformation actually stopped the Black Typhoon from killing everyone in Shin Yokozaki City but Touya was skeptical since it was merely speculation. Touya said that Mei didn't seem surprised about him not being human, but Mei responded she was surprised when she learned about it. However, it would not change how she felt about him. Mei then prepared to go home, reminding Touya not to forget his promise. 
When Touya was visiting Akira in the hospital, Mei called him and told him to meet her in Unomaru's office. Once he got there, Mei noticed that Touya seemed much happier and Touya said it was thanks to Akira, which surprised Mei. After a brief argument, Mei tried to get down to business, telling Touya she had found out more information about how the original Touya died. She said that this information wasn't from Unomaru's journal, but from Ryouko Kagari's notes. She explained about Hinata, the Embryo, being brought to the Wadatsumi Research Facility 12 years ago and the experiments that were performed on her, as well as the circumstances of Touya's death. This led to Touya and Mei's mothers turning against the Takamagahara Group. Touya tried to thank Mei but Mei said it was fine since she got to learn more about her mother and thanked Touya. They lightly chatted about fate bringing them together as a team like their mothers were. As Mei was about to leave, Touya stopped her, telling her he wanted to officially join Sleipnir and Mei accepted. Mei told Touya to start treating her with more respect since she was now his boss but found it too weird. She then gave him a flash drive and told him to look at it when he got home. Mei then asked Touya if he had someplace he had to be and he said yes, so she told him to get going. After, Touya left, Mei vowed to continue her mother's fight. 
One month later, Mei arrived in Touya's classroom and greeted him and Hinata, apologizing for being late. Touya said he needed to get going and Hinata wished him luck with his new job, saying it's a shame Maha Raja closed so suddenly. Touya tried to say that it wasn't a job but decided it's close enough. Hinata then told Mei that she received mail from Kuon, saying that she made it back to Ishana safely and to tell Mei that she would keep her promise on the honor of the true Ten Sages. It also said that, due to Elise's insistence, they would be back in Japan soon. Mei said that meant they'd just have to work even harder. Mei then told Touya to move out and not to fall behind. In the Restricted Ward, Touya asked about the Union they were supposed to be chasing but Mei said that Es-N already took care of it so Touya said he'd see her at school. 
- XBlaze Code: Embryo, Episode 1
- XBlaze Code: Embryo, Episode 2
- XBlaze Code: Embryo, Episode 3
- XBlaze Code: Embryo, Episode 4
- XBlaze Code: Embryo, Episode 5
- XBlaze Code: Embryo, Es & Hinata Route Episode 6
- XBlaze Code: Embryo, Es & Hinata Route Episode 7
- XBlaze Lost: Memories, Green Stone Sub Memory 03
- XBlaze Code: Embryo, Es & Hinata Route Episode 8
- XBlaze Lost: Memories, Azure Main Memory 04
- XBlaze Code: Embryo, Es & Hinata Route Episode 9
- XBlaze Code: Embryo, Es Route Episode 10
- XBlaze Code: Embryo, Es Route Episode 11
- XBlaze Lost: Memories, Black Stone Sub Memory 01
- XBlaze Lost: Memories, Black Stone Sub Memory 02
- XBlaze Lost: Memories, Black Stone Sub Memory 03
- XBlaze Code: Embryo, Es Route Episode 12
|Crossover Characters (BBTAG)|
|Persona 4 Arena/
|Under Night In-Birth|