As Shido wakes up, Reine greets him and informs him that she is the Analysis Officer here. Despite not having a license, she assures him that she could handle simple nursing. Afterwards, she tells him that he was brought to the medical office of <Fraxinus> after they found him unconscious. As Shido prepares to ask more questions, she responds by saying that she is bad at answering questions, so he should save his questions for when he meets the commander of the ship. At that moment, Reine stumbles and hits her head on the wall as she was walking towards the entrance of the room. As Shido voices his concern, she tells him that she has been sleepy recently. Following this, she tells him that she hasn’t had any sleep for 30 years, shocking Shido. She informs Shido that she has an extreme case of insomnia. She then tells Shido that it’s time for her medicine. As Shido voices concern for her health, she begins taking out numerous sleeping pills and consumes them like they were candy. Afterwards, Reine brings Shido to the main deck, where the commander was.
The next day, Shido finds out that a new teacher had collapsed. As it turns out, the person was Reine, who had transferred in as a new physics teacher and the assistant homeroom teacher for class 2-4. As Reine starts a conversation with Shido, she mistakes Shido’s name for Shintarou. Instead of correcting herself, she just starts abbreviating his name to Shin instead. As they proceed to the physics preparation room, she informs Shido that they will begin his training to win over the Spirits. As they are greeted by Kotori, Reine announces the start of Shido’s torture, or training as she quickly corrects herself. As Shido express his shock at having to play a galge, Reine and Kotori looked at him with eyes like he had said something inappropriate. They inform Shido that the game is 15+, rather than 18+. Reine scratches her head, telling Shido that he shouldn’t be able to play 18+ games, since he was only 16. As Shido voices his protest against his training, she states that she would remove an article of clothing every time Shido makes a wrong choice.
For the second stage of Shido’s training, he was told to flirt with actual girls. For Tama-sensei, she gave the Shido the suggestion, via intercom, that he should mention marriage. She figures that a person that was 29 years old like Tama-Sensei would be sensitive to the word. However, she didn’t expect her plan to be super effective. Later, as Shido was about confronted the Spirit, Reine assisted him by using the Realizer to measure the mental of the girl. During the decision making process, Reine voted for option three, since it was the one that made the most sense logically to her and would allow Shido to control the direction of the conversation if it went well. After Tohka rejected the name Tome, Reine voiced her surprise, feeling that it was a great old-styled name.
The next day, Reine and Kotori decide to take their conversation to a family restaurant. Reine asks Kotori why she chose Shido to be the negotiator with the Spirits. In response, Kotori makes Reine promise her that she wouldn’t tell anyone else. Kotori says she is not related by blood with my brother. Neither seeming amused nor surprised, Reine tilted her head slightly. She makes a pose that seemed to be asking if Kotori was deliberately changing the conversation. Kotori follows up by saying that when Shido was adopted, he seemed suicidal because he had been abandoned by his real mother. Reine moved her reacts strangely upon hearing this. When Kotori asked what was wrong, Reine responds by saying that it was nothing and asks Kotori to continue. Kotori tells her that because of this, Shido has become unusually responsive towards the despair in other people, to the point where he would help a complete stranger with a melancholic expression without a second thought. However, Reine responds that she isn’t asking for an emotional response. She questions Kotori on “what exactly is he”. Giving a sigh, Kotori plans to response. However, she unintentionally sprays Reine with water after seeing Shido and Tohka enter the restaurant. Following a delayed reaction, she blew tea towards Kotori after seeing the two together as well.
As Kotori declares F-08•Operation <Tengu Holiday>, Reine’s face twitches, following with her asking if Kotori was serious. As part of the operation, Reine disguises herself as a waitress, leaving a note telling Shido that <Ratatoskr> will assist him from the shadows for the remainder of his date with Tohka. As the date progressed, Reine reports that the numbers were much more stable than yesterday, but Tohka still thought of Shidou as only a trustworthy friend. After Shido was shot accidentally by Origami, Reine remained calm at the situation and continued to observe Tohka's battle, collecting data like everything was normal. After Tohka was sealed, Reine did numerous physical examinations in order to analyze Tohka’s status after being sealed. Then, she did the paper work necessary for her to transfer into Shido’s class, giving her the family name Yatogami in the process.
Reine and Kotori arrive to explain to Shido that they brought Tohka to his house for two reasons. First, it was designed as more training to help Shido approach other Spirits. Secondly, Reine informs Shido that it is part of Tohka’s aftercare. Tohka’s mental state is happiest when she is around Shido. Presently, their is an invisible path between Shido and Tohka that circulates her powers. However, if Tohka becomes upset, her powers will return to her. After that is decided, Reine returns to <Fraxinus> after making the preparations to use the second floors guest room to temporarily house Tohka until the new Spirit mansion was finished building. Later at night, Reine returned and told Kotori that the preparations were complete to move Shido to Tohka’s bed.
After the spacequake alarm went off, Reine pointed the direction for the others to go to the underground shelter. She then caught Shido by the collar and told him that they were going to <Fraxinus>. When Shido asked if it was okay not to bring Tohka along, she responds by saying that it is safe to have Tohka evacuate to the shelter with everyone else, since Tohka isn’t that different from other humans when sealed. After arriving at the bridge of the <Fraxinus>, Reine re-assumes her position of monitoring the Spirit’s mental state.
After Tohka walks in on Shido kissing Yoshino, Reine tells everyone to leave Tohka to her. Then, Reine informs Shido that there are delicate traits in a woman’s heart. The next day, Reine arrives at the Itsuka house to talk to Tohka. Shido informs her that Tohka has locked herself in her room since yesterday. Knocking on the door, she invites Tohka to eat outside, which attracts the hungry Spirit's attention. As they arrive at a restaurant, Reine asks Tohka for the source of her irritation. As Tohka struggles for an answer, Reine replies that it seems Tohka hates it when Shin is with another woman. Tohka replies that she not sure, but she feels frustrated after seeing Shido kiss another woman. Clearing the misunderstanding, Reine tells Shido that the kiss was a complete accident. She assures Tohka that Shido cares deeply for her; otherwise, he would have never risked his life to save her. As Tohka leaves to apologize to Shido, Reine is left wondering what to do with all the food that Tohka ordered.
After Shido confronts the barrier that Yoshino put up, Reine analyzes the constructions and finds that it is a fortress of ice that commences an auto-counterattack when it reacts to the output of the magic attacks from AST’s CR-Units. As Shido finally manages to approach Yoshino, he remembers what Reine told him. From her analysis, Reine conclude that there is another personality within Yoshino that appears only when she wears the puppet. She theorizes that Yoshino probably gave birth to a new personality in order to restrain her own powers from hurting anyone. She then tells Shido that he would be lying if he said that he didn’t want to save this kind and gentle little girl.
At first, Reine is mentioned by Yoshino, as the one who gave Yoshino the sunhat. However, Reine's first proper appearance is on the <Fraxinus>, when Shido shows Kurumi around the school. When the choices come up, Reine is the only one who votes for the third choice, which is to visit the cafeteria.
Later, Kotori takes Shido to the physics lab. Reine is waiting for him there and turns the computer on. Accidentally, Reine shows him the sequel to "Falling Love- My Little Shido", but then shows him a recording of the previous night. In it, Kurumi is killed by Mana Takamiya. Once it ends, Kotori and Reine encouraged Shido to invite Kurumi out on a date before she gets killed again. When Shido has to date Tohka, Origami and Kurumi at the same time, Reine compliments Tohka's clothing. Once Shido meets with Kurumi, the choices for the date come up, and suggests that number three (go to a lingerie shop) is a good choice, based on Kurumi's previous actions. Later that night, when Tohka tries to encourage Shido to save Kurumi, she mentions that Reine told her what happened between Kurumi and Mana.
Afterwards, Reine is shown in the Fraxinus researching Mana. She makes a complicated face as she explains to Kotori that Mana is indeed Shido's blood related sister. Also, she's not from the AST, but rather from DEM. When Reine tells the commander about Mana's body being engineered with magic, she seemed furious, surprising Kotori as she had never seen her like that. When Shido prepares to confront Kurumi at school, Reine tells him that Kotori has gone away for an urgent matter and that she would guide him today.
Once Kurumi activates her <City of Devouring Time>, Reine briefs Shido on it, stating that it is indeed caused by Kurumi. Later, when Shido is facing Kurumi at the rooftop, Reine informs him of her mental state. When Kurumi summons a spacequake, Reine tells Shido that it's like Kurumi is afraid of him. Shido decides to jump off the rooftop, and asks Reine if he would survive, to which she says he'll most likely will. However, she is surprised when Shido actually jumps of the roof.
As Shido wakes up on the Fraxinus medical bay, Reine calms Shido down as he frantically asks questions about what happened to everyone. She informs him of what happened and confirms that everyone is alive. When he asks her about Kotori, Reine and Yoshino accompany him to the quarantine room. Once they get there, Yoshino leaves and Reine tells Shido that he must go alone to speak to Kotori. While Shido is talking with her, Kotori grabs her hand and begins to groan. Reine interrupts them, asking Shido to leave them alone for a while. When Reine comes out of the room, she tells Shido that Kotori is alright for now. She then asks Shido to invite his sister to a date in two days, as they need to him to seal her powers. Upon Shido asking her about this, she informs him that Kotori won't be able to hold on for much longer, and that she needs sedatives and stabilizers. She then asks Shido to go to the hospital to check up on Mana, while she takes care of Kotori. Shido notices an oddity in Reine's voice as she says this.
When Shido is leaving the hospital, Reine calls him to ask him if he is done visiting Mana. After Shido states that he wasn't allowed to see her, she responds back in a low and painful voice. As Shido asks if something is wrong, she tells him it is nothing and asks him if he can return to <Fraxinus> as soon as possible, since they are about to have a strategy meeting. She also tells him that, compared to Tohka and Yoshino, Shido has the advantage this time, since he knows a lot of things about Kotori.
When Shido gets to the Fraxinus, Reine waits for him to speak with Tohka, and then takes him to the meeting room. When Kannazuki starts the meeting, Reine suggests Shido to cover his ears, and then all the crew members start shouting their love for Kotori, as Reine explains it. During the meeting, Kagawoe is rewarded a Saint Kotori (Sacred Kotori Medal). As Shido asks Reine what it is, she says that those are badges made by Kannazuki with Kotori's photos. Reine also reminds the crew that their Hot Spring plans would fail, since Kotori doesn't have a lot of time. She then asks Shido if Kotori ever mentioned going to a certain place, to which Shido replies that she wished to go to the Ocean Park. Although she was in Imouto Mode when she said that, Reine says that it doesn't matter, since that mode is a way for her to tell him how she really feels.
The next day, Reine informs Shido that he'll be training for Kotori's date by helping Tohka and Yoshino pick swimsuits, since he needs to get used to female swimsuits. When Origami appears, Reine says that this was not part of her plan. When Tohka starts arguing with Origami, Reine simply tells Shido to make something up. When Origami asks about the spirit of fire, Reine asks Shido to calm down. Once that is over, she suggests Shido to invite Origami to come pick swimsuits as well; adding that having more girls as specimens isn't a bad thing. Once they are picking the swimsuits, Reine asks Shido not to panic over the girls' "charming figures". When Tohka mentions that whoever makes Shido's heart beat the fastest get a date with him, Reine says that she increased the difficulty slightly. Every time one of the girls made his heart beat, Reine dictated a punishment for Shido, such as taking Kotori to her bed.
On the day of the date, Reine quickly informs Shido that Kotori is on her way to the station. When Kotori finally appears, Shido stays silent, and is scolded by Reine for this. Once Shido sees Tohka and Yoshino, she tells him that they'll be tagging along. When Shido asks Reine about Kotori's mood, she simply wishes him good luck. Later, when Shido sees Tohka and Yoshino in their swimsuits, Reine says that it was a good thing that they have practiced. When Kotori appears with her swimsuit on, however, Reine reminds him that he should complement her. When Shido says that Kotori's budding breasts are irresistible, the commander gets angry, and Reine informs Shido that there's an emergency. Not with Kotori, but with Yoshino. Later, when Kotori asks him if he was telling the truth about her breasts, Reine tells Shido that lies and feelings cannot coexist, so Shido must tell her that this is how he really feels.
Afterwards, Reine says that Shido could play the hero by saving Kotori from three Fraxinus crew members who were disguised as criminals, but Kotori ends up recognizing them. Reine then mumbles to herself about it, saying that she underestimated Kotori. When the choices come up again, Reine instructs Shido to ask Kotori to go to the water slide. When Tohka says she wants to go too, Reine suggests he lets her. She later reveals that it was for the best to let Tohka go because that would make Kotori jealous, and she'd agree to go down the water slide together. After an incident involving Tohka's bikini loosening up, Reine tells Shido that Kotori's mood has remained the same for the entirety of the date. When he contacts Reine again, he is told that she has temporarily left. When Shido goes to the bathroom, he sees two people talking behind the vending machines. The two people were Reine and Kotori, and Reine was giving Kotori drugs in order to calm her. As Reine tells Kotori to not push herself to hard, Kotori responds that it should be fine since she is a Spirit right now.
Once they are done, Shido confronts Reine about it, and she tells him that Kotori wished to go a date with Shido without him feeling compassion or pity for her. As a result, she begs him to pretend that he hadn't seen anything for Kotori's sake. Later on, when Shido decides to take the lead for the date, Reine says that he is doing well, and that maybe they were worrying for nothing. After Origami and Kotori's fight, Shido is on the Fraxinus Bridge talking to Reine. She informs him that Origami could get suspended and apologizes for worrying Shido so much, since the date wasn't necessary to seal Kotori's powers. After all, Kotori loves her brother the most. As she said that, Kotori kicks Shido, who ends up burying his face on Reine's chest. The commander says that there's an error with the numbers, but Reine interrupts her, saying that such a thing is impossible. Kotori then bribes Reine with Ten "La Pucelle" limited edition cream puffs. Reine accepts and tells Shido that the numbers must have been wrong.
When disguised as <Phantom>, Reine appeared before Kurumi as she was struggling to regain the time she had lost during her fight with Kotori. Here, it is revealed that a month ago, she was the one who told Kurumi about Shido’s existence and his power to seal Spirits. She then asks Kurumi how it went with Shido, to which Kurumi replies that she cannot give up on Shido, as he is a large reservoir of spirit power for her to consume, which would allow her to use Yud Bet, the <The Twelfth Bullet>. <Phantom> questions her on why she would want to travel back in time, surprising Kurumi on how the mysterious person covered in noise had already knew about her angel’s powers. When Kurumi states that her motives are to travel back in time to 30 years ago to kill the First Spirit, she mocks Kurumi for being surprisingly gentle. As Kurumi prepares to retaliate for the insult, <Phantom> disappears into the darkness.
Reine Murasame is first seen talking with Kotori on the Fraxinus Bridge. She explains to the commander that the school trip’s destination has changed to Arubi Island, and that this is due to an offer from Cross Travel, a company affiliated with DEM industries. Kotori insists that Reine should go on this trip to relax, since Kotori must attend to a Ratatoskr meeting. In response, Reine says that it should be fine if Kannazuki takes care of <Fraxinus>. While in the island, Shido witnesses a duel between the Spirits Yamai Kaguya and Yamai Yuzuru. When he asks them to stop, Reine contacts him and requests him to explain the situation, but Kaguya interrupts them.
When Shido takes Kaguya and Yuzuru to the rest of his group, Reine explains that they are transfer students. She then asks Shido and the Yamai twins to come with her to explain some things (and to let Tohka rest, who got hit in the head by a flying garbage bin). Reine and Shido hear the story of the original Yamai, and Reine says that communication with <Fraxinus> has been lost. She then asks Kaguya and Yuzuru to go with her, to which they reluctantly agree after hearing that she can help them win over Shido. Afterwards, Shido is tricked by Kaguya and Yuzuru to enter the female hot spring, and he ends up coming to Reine's room, dripping wet. Then, Reine tells him that she can't communicate with <Fraxinus> yet. She explains that Kaguya and Yuzuru are the Spirit(s) <Berserk>, who are quite famous due to their weather disasters they cause when appearing in this world. The spacequake this time happened far above in the skies of the Pacific Ocean. Kaguya and Yuzuru likely created a cyclone that blew them to Arubi Island. She comments that this is a lucky opportunity for Shido, since it was rare to see <Berserk>. However, they still need to be cautious, since if Shido kisses one of the twins, the one with the powers left would get angry and the inhabitants of Arubi Island might get caught in the crossfire.
They then come up with a plan to seal the twins' powers. Reine would give intercoms to Kaguya, Yuzuru and Shido, and she'll give advice to the three of them, hoping to control Kaguya and Yuzuru's actions to a certain extent. When she notices that Shido caught a cold, Reine asks him to sleep in her room. 20 minutes later, Kaguya and Yuzuru come to "nurse" Shido. Reine's plan was to study their movement patterns and increase their intimacy points. On the next day, Reine tells Shido that Kaguya and Yuzuru have finished changing their clothes. She reminds him that the girls also have intercoms, so she will be providing advice for them as well. She also reminds him to compliment the girls’ swimsuits.
Reine ends up giving them funny advice for the date. Later on, Reine, Tohka and Origami appear, and Reine suggests that they should play beach volleyball. In order to improve the relationship between Shido and the twins, Reine separates them into two groups: Tohka, Origami and herself against Shido, Kaguya, and Yuzuru. After the match, Reine tries to talk to Shido through the intercom, but is interrupted again by Kaguya. However, she manages to hear what the twins want for each other, complicating the situation.
Later that night, Reine interrupts them Origami faces a Bandersnatch, asking Origami to come inside. When the robot charges at Reine, Origami pushes her away after receiving a blow to her stomach. Afterwards, Origami wakes up in Reine's room. She had been taking care of her, and tells Origami that the doll stopped moving after she fell unconscious. She then listens to Origami as the AST member voiced her desire to get stronger. When they are leaving the island, Reine explains to Shido that Kaguya and Yuzuru have been given permission to ride the plane, since they wanted to be with Shido.
Reine is on board <Fraxinus> when Shido first meets Miku. Reviewing the choices, she says that the second choice (praise her singing voice) is the appropriate one, since they know very little about the Spirit <Diva>. Later, she shows Shido a diagram of Miku's mental state from yesterday. Based on comments from the crew members, they determined that Miku might be into girls. When Shido (dressed as Shiori) is working at the maid cafe, Reine and Yoshino show up. She explains to Yoshino that Shido is not doing this because he wants to. The two girls then enter the maid cafe.
After Miku uses her Angel, <Gabriel>, on the audience, Reine finds that the <Fraxinus> crew, except for Shiizaki and maybe Kannazuki, have been brainwashed. Luckily, Mana appears and knocks out all of the brainwashed crew members. Then, Reine explains to her that this was caused by a Spirit, and that she has to save Shido and Tohka.
When Shido infiltrates the DEM building, Mana gives him an intercom which allows him to communicate with Fraxinus. There, Reine explains that they used Mana's Territory to purify the area, and it took them some time to recover. Later, Reine says that he should look for Tohka in a place similar to the containment area on board <Fraxinus>.
Reine helps Shido with his dates after Natsumi sent him the twelve photos. The day before, they talk about Natsumi's strategy, and Reine says that <Ratatoskr> will place mana observations on everyone in the pictures. But since Natsumi's reading could be low, she asks Shido to date all the 12 suspects to find out if something is amiss. She also says that Kotori won't be able to enter <Fraxinus>, as she is one of the suspects.
During the date with Tohka, Reine tells Shido to "stir her up a bit". However, when Tohka begins show a strange behavior (she doesn't want to eat a lot), Reine tells him to calm down and see what happens. The second date is with Yoshino, and Reine tells Shido that she should be on her way. However, there seems to be nothing strange with her. However, when Yoshino licks Shido's face, they begin to have doubts. The third date is with Tonomachi. Reine had arranged it to be in a sauna, since Natsumi would hesitate being naked in front of a male. Since Tonomachi shows no reaction, Reine asks Shido to touch him several times, which freaks both of them out.
The next date is with Yuzuru. Reine asks Shido to hurry, since he's a little late. That night, Reine is with Shido and Kotori in their house. Reine says that, despite letting Yuzuru walk alone at night, he did a good job. She also tells him that the next date will be with Kotori. However, during the night, Yuzuru disappears, and Reine shows Shido a recording of her being sucked into <Hanie>l. After seeing this, Reine tells Shido to find Natsumi as soon as possible. During the date with Kaguya, Reine says that it is nice for her to be lively. When Kaguya makes a bet with Shido, Reine tells him that they'll stop her if her request is too aberrant.
Afterwards, Reine reveals that the next date will be with Ai, and tells Shido that she placed a letter on her shoe rack asking her to go to the coffee shop in front of the station. During the next day, Shido and Reine discuss Yoshino and Ai's disappearances, and she insists that it was not his fault. During the next date, Reine tells Shido that Origami has been waiting for him for an hour. When Origami pays for the movie tickets and asks Shido to leave his money for later, Reine concludes that Origami won't let him leave immediately after the movie ends. Later that day, Natsumi informs Shido that now Tohka has disappeared. When only Kotori, Origami, Miku and Kaguya are left, Kotori says bad things about Natsumi's body to lure her out, but Reine says that nobody has reacted to her taunt.
When Shido is taking care of the girls (who had been turned into children by Natsumi) Reine comes over to help him. First, she has Kaguya and Yuzuru apologize to Kotori for stealing her candy. Then, she asks Tohka to wait for the meal and gives her a cookie. She also tells Origami that Shido prefers girls who can go to the toilet alone. After that, she calms down Yoshino and tells Miku that Shido is not ignoring him. When Shido thanks her and says that she looks like a mother, Reine reacts strangely, but claims not to be bothered by it.
Afterwards, when Natsumi turns Shido's house into a human zoo, Reine informs him that they've found Natsumi, who's hiding in a building under construction. On the Ratatoskr building, Reine explains Natsumi's mental state to Shido, saying that she is not used to being praised while in her real form, and that she doesn't seem to believe that anyone could accept her.
When they find out about DEM's artificial satellite, Reine explains that due to the explosives and the <Bandersnatch>s' Territory, the explosion would be similar to a tactical nuke. When Kotori decides to use her Spirit powers, Reine asks her if she really is okay with that. After blowing up the first artificial satellite, Kotori wants to use her powers one more time, but Reine stops her by saying that it would be too much of a burden for both her and <Fraxinus>.
When Shido goes missing, the space quake alarm sounds, but since there are no mana readings, Reine claims that it could be a false alarm set up by DEM or the JGSDF. However, she states that it is still dangerous to think it's only a false alarm.
In the present time, Reine, as <Phantom>, approaches Origami after she had been defeated by a full-powered Tohka. She offers Origami an absolute power if she reaches her hand out. Despite thinking it was a hallucination, Origami accepted the offer and absorbed the white gem that Phantom gave to her, turning Origami into a Spirit.
Having traveled back to 5 years in the past thanks to Kurumi’s <Yud Bet>, Origami attacks <Phantom>, startling her with the sudden ambush. Taking a good look at her, <Phantom> realizes that she was in possession of the Angel <Metatron>, which should be impossible since the Sephira Crystal that holds that angel is still in her possession. Remaining calm while Origami desperately tries to kill her, <Phantom> deducts that Origami must have used Kurumi's Angel <Zafkiel>'s twelfth bullet to travel back in time, which causes <Phantom> to voice her surprise, since she couldn't imagine Kurumi lending her powers to someone else.
During their short fight, <Phantom> notes that Origami must have a large grudge against her future self, but she couldn’t let her kill her because she has a wish that she wants to fulfill. <Phantom> asks Origami why she is trying to kill her, and Origami tells her that it's because <Phantom> is planning to kill Origami's parents. <Phantom>, however, has no such intention and tells her so, but her reply only enrages Origami more.
Origami manages to remove <Phantom> noise with an attack from <Metatron>, but is temporary blinded by the attack and is unable to clearly see <Phantom>'s true appearance. However, she did note that <Phantom> is a young girl with long hair and that her true voice sounded familiar to her. <Phantom> noted to herself, that with such talent, it would be unthinkable to not make Origami a Spirit, even if she would one day turn against her. <Phantom> then, despite Origami's attempt to stop her, disappeared into the void.
Phantom is later approached by Shido, who had traveled back to 5 years in the past twice in order to change the future. Shocked by Shido’s appearance, she quickly tries to flee from the scene. However, <Phantom> eventually stops and waits for Shido, stating that she left because she didn’t want to cause a scene in front of Kotori. She also voices her disappointment that Shido gave the name <Phantom> to her. However, in order to communicate with him, she decided to use Rinne Sonogami’s appearance, as she couldn’t let Shido see her true form yet.
Using Shido’s appearance as her basis, she correctly deduced that Shido came from 5 years in the future and had Kurumi’s help to travel back in time. <Phantom> is then inquired by Shido, who wants know who he is and why he has the power to seal Spirits. However, she couldn’t give him an answer, as she knows nothing about his prior circumstances and Kurumi is currently eavesdropping on their conversation.
Instead, she asks why Shido went through all the trouble of traveling back in time. Shido replies that she wants Phantom to disappear, which she interpreters as him wanting her dead. She bemuses that she had thoughts about this happening, since she had an idea that he will be at his wits end dealing with moody Spirits in the future. However, she quickly retorts that she didn’t want to think like that.
In response, Shido clarifies that he just wants <Phantom> to return back to the other dimension. When she asks for the reason, Shido hesitates on his answer, as he didn’t know if <Phantom>’s goal is to invert the Spirits like Westcott. Nevertheless, <Phantom> refuses on the basis that she still had some jobs left to do. Before Shido can respond, he finds his body frozen. <Phantom> touches his cheek and repeats the words that he heard when he woke up on Ratatoskr after his first time meeting Tohka: “…Because I definitely won’t let you go again. I definitely won’t make a mistake again.” <Phantom> then kicks the ground and disappears into the sky just as Origami arrives back in the past.
In the new timeline, Reine is at Shido's home with him and Kotori. There, Shido explains how he knew Origami and that he changed the history with Kurumi's help. During a discussion with Shido and Kotori, Reine states that Shido is able to remember the past due to either being the one who changed history, or as a result of being affected by <Zafkiel>'s powers. Then, Reine theorizes that maybe the Origami from the new timeline and the Origami from the old timeline are not the same person, and that <Devil> appears once she detects Spirit mana. They decide to do what they always do and have a date with Origami. 
During their date, Shido loses track of Origami, and Reine confirms that she in 20 meters behind him, in a dressing room. When Shido and Origami are in the park, Reine says that Origami is anxious and that Shido needs to reassure her in order to perform the sealing. However, when Shido starts using Kotori's power to heal from his injury, Reine's speculation is proven correct as Origami inverses.
When Kotori is wondering about Phantom's identity, Reine comes in to tell her that there is a problem with someone’s Reiha readings. However, the Spirits' mental state is good. When Shido is taken to the underground <Ratatoskr> building, the Spirits are there waiting for news, and Reine says that Miku is in Kansai due to her job. Once Miku arrives there, Reine explains Shido's condition to the girls, and explains that they need to kiss him in order to get him back to normal. However, when they go to the medical room Shido is staying at, he is no longer there. When the girls are looking for him, Reine calls them, saying that she's found him, and that they should see it themselves.
Afterwards, Reine decides to help the Spirits with intercoms in order to make Shido fall for them. She warns the girls to not to use their powers, since she doesn't know what effect it could have with the Path blocked. Before the date begins, Origami explains to the Fraxinus crew that her idea was a nudist beach, to which Reine says that it could shock Shido. Origami suggests stripping gradually, but her request is denied again.
Once the date begins, Reine gives advice to both Kaguya and Yuzuru, asking them to pinch Shido from the left and the right, and attack him by pushing their breasts on him. Since that doesn't work, she asks them to perform a vanilla flavor kiss through an ice cream. Once the twins succeed, Reine congratulates them. When it's Natsumi's turn to make Shido's heart race, Reine suggests Natsumi to go with Option 2: Have a gap contest by handling him with the composure of an adult "Onee-san". However, when she transforms, Reine says that it's too dangerous and that she should go back to her original form. But once she runs out of power, Reine congratulates her for moving Shido's heart. Later, Reine encourages Yoshino to go with Shido. Reine confirms that Yoshino is doing a good work when she starts applying sunscreen over Shido.
However, they are interrupted by DEM, and Reine says that one of the readings belongs to Ellen Mathers. Seeing that their objective is Shido, she asks the girls to keep conquering Shido, since she has a countermeasure planned, though she didn't want to resort to it if necessary.
Later, just as Shido was about to be hit by the blast shot from <Dainslaif>, Reine arrives in her <Phantom> disguise and creates a barrier to save Shido’s life. She then weakens some of the Spirit power surrounding Shido in order to give the sealed Spirits a chance at saving him. Before leaving, she calls all of the sealed Spirits her “children”, and wishes them good luck.
Reine is first seen in the Ratatoskr building analyzing Shido's condition. She says that Shido's mana levels are going back to normal and that he can go back to the usual medical checkup. Then, she says that it will be necessary to clear up the misunderstandings with Shido's physical measurements, and with Ai, Mai, Mii and Tamae. Later, Shido finds Kotori and Reine trying to restrict Mana, who was trying to avoid her check up appointment. Kotori and Reine are trying to analyze Mana's condition, but the girl is stubbornly refusing.
After Shido's date with Nia, Reine says that her love values increased when he cosplayed as Tokiya, and that he needs to act as a 2D character in order to win Nia over. While this seems impossible, Reine says that she has some ideas. Once they watch Nia play Ratatoskr's game, Kotori asks Reine why she had such a game, to which she replies that it's better to be prepared. Reine is later seen at a cafe talking with Takajou-sensei, an acquaintance of Nia's. She then sets up the conversation for Shido and Kotori to talk to Takajou-sensei
Later on, after Westcott takes Nia's Qlipha crystal, Reine is taking care of her after her treatment with the medical Realizer is completed. After telling Shido and the others that Nia’s condition had stabilized, she gives Shido permission to take Nia outside for a while to see the fireworks of the New Year.
After the meteor incident at school, Reine helps transport Shido, Tohka, Origami, and the Yamai Sisters to the new underground Ratatoskr base. Reine is among the Fraxinus crew present when they show Shido the footage containing the new Spirit, <Zodiac>. The new Spirit was likely found by DEM through Westcott's <Beelzebub>. They send an armada of ships to capture her, but <Zodiac> easily repels them by using her Angel, <Michael>. From the analysis of the video, Reine concludes that <Michael> has the power to seal the target’s function by impaling it with the key and alter the very fabric of space-time to create wormhole where she can also set its destination. The meteors dropped today were likely sent by <Zodiac> in retaliation for disturbing her rest.
Using a Realizer they project a 3D image of Shido in order to be able to converse with <Zodiac>. As Shido approaches the new Spirit, he finds himself being attacked unconditionally. While lost in thought, Reine touches her chin and states that she didn't expect her to be so violent, but it seems like using the hologram was the right choice. As Shido tries to communicate with the new Spirit, Mukuro, Reine emits a dejected voice that his determination may not last long. When asked what is the matter, Reine motions towards a statistical table on the monitor. It appeared to display Mukuro’s happiness levels and mental state and showed in the chart indicates absolutely zero deviation.
After Shido receives a scathing rebuttal from Mukuro, the other Spirits suddenly crash out of their hiding spot, revealing that they were eavesdropping on the conversation. As Kotori turns to Reine for advice, Reine gives a go with the expression that makes Kotori yield and let the other Spirits stay and help. As they are discussing how to win over Mukuro, Reine remarks that the primary problem lies in how Mukuro sealed away her own emotions using her Angel. Therefore, she could likely use her Angel again to reverse the process. However, Shido still notes the extreme difficulty in achieving that, comparing it to trying to unlock a chest with the key inside. Much later, Reine accompanies everyone else to the secret Ratatoskr base where the new Fraxinus is being built. As DEM launches their attack, Reine and the other crew members help defend the ship from the invading Wizards. After securing their position, Reine begins to provide first aid to Nakatsugawa, who had injured himself in the process. After Kotori and her group arrive, the new Fraxinus EX begins its maiden voyage into space in order to start the mission in saving Mukuro.
As Shido was about to prepare for his date with Mukuro, he starts to panic after realizing that he had no way of contacting her. However, Reine tells him not to worry, being the only one to see the spacial gate opened behind Shido as Mukuro arrives to sweep him away.