Mitsuki Mononobe
Mitsuki Mononobe
Vital statistics
Name Mitsuki Mononobe
Kanji 物部 深月
Romaji Mononobe Mitsuki
Gender Female
Birthdate March 3
Affiliation Midgard
Status Alive
Occupation Student
Lieutenant Colonel
Relatives Kazuki (Father) †
Misaki (Mother) †
Kai Mononobe (Adoptive Father)
Yoshimi Mononobe (Adoptive Mother)
Yuu Mononobe (Adoptive Brother)
First appearance
Light Novel Debut Volume 1
Manga Debut Chapter 0
Anime Debut Episode 1
Seiyuu Manami Numakura

Mitsuki Mononobe (物部 深月, Mononobe Mitsuki) is one of the main female characters in the Unlimited Fafnir series. She is a D, Student No 3 of Brynhildr Class, the Student Body President and Captain of the Dragon Subjugation Squad with the rank of Lieutenant Colonel, along with being Yuu Mononobe's adoptive sister.


Mitsuki is portrayed as a young pretty girl of average height with blue eyes. Yuu describes her as having snow-white skin, gorgeous long black hair and petite, yet beautifully shaped, breasts. She is usually clad in Midgard Academy's standard female uniform, wears black colored knee socks and heels and a light blue scrunchy is tied onto the left side of her hair. Her dragon mark is situated on the back of her neck.


Mitsuki is shown to have a rather professional and mature attitude, even when speaking with her brother, taking her role as the Student Body President and Captain of the Dragon Subjugation Squad very seriously. During her speeches to the student body, she displayed a fair amount of charisma and is shown to be quite popular with the students. She is also calm and collected during battles, along with being a capable strategist. However, she tends to shoulder all responsibilities by herself and blames herself whenever things go wrong, as was shown in Miyako's case. However, this attitude is toned down a bit after Basilisk is defeated and Lisa forgives her for what happened to Miyako. According to Yuu, Mitsuki is quite stubborn and has a competitive streak, along with suffering from a mild case of eighth-grade syndrome. 

When she was younger, Mitsuki spoke in a more childish manner. She also came off as shy, introverted and disliked showing herself in public. These aspects of her personality were gone after the incident with Miyako.


Mitsuki was born in Nanato City, Japan, where she grew alongside Yuu Mononobe, her neighbor. The two of them became friends quickly, with Mitsuki developing romantic feelings for Yuu. During one of their visits to their favorite observation spot, Mitsuki declared her wish to marry Yuu, kissing him on the lips as proof of their engagement. However, some time later when she was 6 years old, while on a trip to a camping spot with Yuu and her parents, a car accident caused by the Ninth True Dragon occurred, which resulted in the deaths of Mitsuki's parents. Furthermore, the True Dragon was sealed inside her by Yuu's Authority and the siblings' powers as Ds awoke as well. Afterwards, she was adopted into the Mononobe family as a daughter, something which distraught her greatly since her wish to marry Yuu could not be fulfilled now. When Yuu found her after she ran away, Mitsuki lashed out at him in anger, but was reassured by Yuu that he would still keep their promise even if they had now become siblings.

Three years before the start of the series, at the age of 13, Hekatonkheir attacked Nanato City. Although everyone evacuated, Mitsuki stayed behind, trying in vain to fend off the Dragon with her powers. When Yuu tried to persuade her to run away, Mitsuki tearfully stated that this was the town where they could be a family, refusing to back down. After Yuu destroyed Hekatonkheir with his Anti-Dragon Armament by borrowing dark matter from Mitsuki, she could only watch helplessly as he was taken away NIFL, having claimed that he was the only D present. A month later, out of a desire to see Yuu again, Mitsuki outed herself as a D and was sent to Midgard, where she was surprised to see that Yuu wasn't there. She confronted Midgard's principal, Charlotte B. Lord, about this, who promised to look into the matter. Afterwards, she was assigned to Brynhildr class. Two weeks later, Mitsuki met Miyako Shinomiya for the first time, with the two becoming close friends quickly.

However, one year after Mitsuki's arrival on Midgard, 'Purple' Kraken attacked the Academy with the intent of claiming Miyako, whom she had marked as a mate. Mitsuki was sent out as a member of the newly formed Dragon Subjugation Squad to intercept it and was confused when Miyako claimed that she was the Dragon's target. As a result, Kraken succeeded in trapping everyone and transformed Miyako into a Kraken as well when she charged it. At that moment, Mitsuki heard Miyako's voice in her mind, urging her to shoot Kraken. She did so and was surprised to see that she could generate antimatter, destroying the dragon. While torn over having to shoot Miyako as well, Haruka Shinomiya ordered her to fire, something which Mitsuki tearfully did. Her relationship with Lisa Highwalker also soured because of this incident, although Lisa only acted so in an attempt to ease Mitsuki's guilt. Afterwards, she rose to the position of Student Council President and Captain of the Dragon Subjugation Squad on account of her deeds, despite her wishing for punishment and condemnation.

Two years later, shortly before the series' start, Mitsuki managed to locate Yuu within NIFL and used her authority to convince them to transfer Yuu to Midgard.


Dragon's EdenEdit

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Mitsuki after addressing Yuu

Mitsuki was introduced for the first time in Volume 1, interrupting Yuu and Iris Freyja's conversation. After escorting Yuu to her living quarters, he informed him that he would be a student of Midgard from now on and scolded him for the inappropriate behaviour he exhibited with Iris. The next day, Mitsuki introduced Yuu to the school assembly and brought him to Brynhildr Class, where she was forced to deal with Lisa's objections. Mitsuki calmly refuted Lisa's claims of abusing her power and scolded Yuu afterwards for transmuting a gun. When Yuu proposed the idea that he and Iris do special training, Mitsuki agreed to supervise them and offered helpful suggestions to both of them during practice. During the selection test for the Dragon Subjugation Squad, Mitsuki was responsible for supervising the participants alongside Haruka, and was the one who noticed that Yuu's plasmafied bullet had actually pierced the target diamond.

When it became known that 'White' Leviathan was approaching Midgard, Mitsuki addressed the student body and asked the D whose dragon mark had changed color to step forward, declaring that everyone in the Dragon Subjugation Squad would fight to the last to protect her. Upon discovering that Iris was the one, Mitsuki declared a level A alert. After returning back to her quarters, Mitsuki was approached by Yuu, who told her about Loki Jotunheim's message to him and asked her to be assigned as Iris' bodyguard in order to restrain NIFL. Mitsuki agreed, on the condition that she would be the one to kill Iris if it came down to it, brushing aside Yuu's protests by stating that her hands were already stained with blood. Mitsuki directed the Dragon Subjugation Squad's attack against Leviathan, but the Dragon's powerful repulsive field rendered every attack ineffective.
V1 I9

Mitsuki appears to confront Yuu and Iris

When Leviathan breached the third defensive line, Mitsuki appeared before Yuu and Iris with the intent of killing Iris. This led to a fight between Mitsuki and Yuu, which Mitsuki lost when Yuu applied a light chop on her head, which was how they resolved their fights when they were young. Mitsuki agreed to keep fighting and lent her dark matter to Yuu so that he could construct an Anti-Dragon Armament, which unfortunately proved ineffective against Leviathan. However, Yuu constructed a new Anti-Dragon Armament, Marduk's Main Cannon, Babel, which gave an opening for Mitsuki to strike the dragon with her antimatter arrow, making it explode from within, while Babel crushed its body. In the aftermath of Leviathan's demise, Mitsuki reprimanded Yuu for his insubordination and inappropriate behavior, promising to have him write at least a hundred repentance essays.

Scarlet InnocentEdit

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Mitsuki in the bath with Yuu and Tear

In Volume 2, Mitsuki was the one who introduced Honoka Tachikawa and Tear Lightning to the school assembly. When she attempted to pacify the students, who were alarmed by Tear's horns, by stating that Tear was human, she was met with an outburst from Tear, who declared that she was a dragon and lashed out with her powers. Fortunately, Yuu was able to calm her down before things got out of hand. While Yuu was tutoring Tear, Mitsuki also tried to assist by teaching her the rules of Midgard, but was unsuccessful due to Tear's obstinate belief that she was a dragon. Later that night, Mitsuki had a discussion with Yuu about Tear's behavior and explained how Tear was discovered in the custody of the Sons of Muspell. Mitsuki also took part in Brynhildr Class' beach party, scolding Yuu for his comments on everyone's swimsuits.

When Hekatonkheir attacked Midgard, Mitsuki took command of the Dragon Subjugation Squad and issued her orders to everyone before approaching the Dragon, accompanied by Iris and Yuu. She, Iris, Firill Crest and Ren Miyazawa launched attacks against the Dragon, but failed to inflict any lasting damage due to Hekatonkheir's regeneration abilities. Mitsuki proceeded to gather the entirety of the Dragon Subjugation Squad in Yuu, Tear and Lisa's location. Thanks to Yuu's newly acquired antigravity power, Mitsuki and the Dragon Subjugation Squad were able to push Hekatonkheir to the sea, where Yuu destroyed it by using an Anti-Dragon Armament.
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Mitsuki smiles after hearing Yuu's declaration

Following the conclusion of this battle, Mitsuki visited Yuu in the infirmary, questioning him about his new found power. When Yuu failed to answer, Mitsuki demanded to know if it was true that he and Iris had kissed. Upon hearing Yuu's confirmation, Mitsuki asked him to handle things honestly and also to forget about their childhood promise. She was, however, taken aback when Yuu resolutely declared that he would not forget and that he would not give up on her happiness after she told him how she outed herself as a D and how she would keep fighting dragons as atonement, prompting her to smile and call him hard-headed.

Crimson CatastropheEdit

V3 I3

Mitsuki gets into an argument with Lisa

As the leader of the Dragon Subjugation Squad, Mitsuki was also one of the members chosen to participate in the operation against 'Red' Basilisk in Volume 3. Although she attempted to prevent Yuu from joining as well, her decision was vetoed by Haruka, who believed that Yuu's anti-gravitational matter might prove useful, much to her displeasure. En route to the volcanic island chosen as the battlefield by ship, Mitsuki got into an argument with Lisa regarding the matter of Miyako's death. When she walked on Yuu and Firill in an compromising position later on, Mitsuki once again scolded Yuu, but was surprised and embarrassed when he asked her to sleep in his room with him. After Yuu asked her about Miyako, Mitsuki was hesitant to talk about her, but eventually agreed, on the condition that she would be allowed to hug Yuu. Upon finishing her tale, Mitsuki was surprised when Yuu asked her to look at things from Lisa's perspective and seek her forgiveness. Although reluctant at first, Mitsuki promised to do so. When the Dragon Subjugation Squad reached the volcanic island, Mitsuki joined her classmates in taking a bath on the island's hot spring. There, she almost discovered the concealed Yuu (who was also there due to Firill's machinations), but was interrupted due to an emergency call, which stated that NIFL would begin its operation against Basilisk the next day.

Following NIFL's failure to destroy the Dragon, Mitsuki and Haruka devised a new plan to destroy Basilisk, which involved sniping it by using the volcanic island and the horizon as cover. However, the Dragon predicted their attack through unknown means and counterattacked with the enhanced Catastrophe. Mitsuki then attempted to blow up the island by borrowing dark matter from Ren to form an enhanced antimatter arrow, but Basilisk once again predicted their actions and struck with the enhanced Catastrophe. Mitsuki and Ren were almost caught up in the beam, but were saved by Yuu's repulsive field.
V3 I8

Mitsuki and Lisa celebrate Basilisk's destruction

Although things seemed hopeless, Yuu proposed a new plan based on the assumption that Basilisk could not fire the enhanced Catastrophe for more than five seconds, which involved the use of NIFL's anti-Basilisk bomb, Mistilteinn. However, conflict arose when Mitsuki declared that she would descend along with the bomb in order to control its trajectory. When everyone else also volunteered, Lisa announced to a bewildered Mitsuki that she was wiling to forgive her if she drafted a perfect plan that would allow all volunteers, including herself, to come back alive from this operation. Thanks to Mitsuki's plans, the operation was a success and Basilisk was destroyed, with Lisa forgiving Mitsuki as she had promised, despite the latter's reluctance. After the victory party, Mitsuki approached Yuu and thanked him for everything he had done, while also declaring that she would not give up on him and that her feelings for him would never change.

Spirit HowlingEdit

V4 I4

Mitsuki in her formal dress

Following the announcement that Kili Surtr Muspelheim had sought refuge in the Principality of Erlia and was requesting for Midgard's Ds to pick her up in Volume 4, Mitsuki joined the escort mission as a member of Brynhildr Class. During 'Yellow' Hraesvelgr's attack at the royal ball, Mitsuki led the Dragon Subjugation Squad in an attempt to intercept the Dragon, but all their attacks proved to be ineffective. After being paralyzed by Hraesvelgr's Ether Wind, Mitsuki and the rest could only watch as the Dragon consumed Albert Crest's soul, which had materialized due to the Ether Wind and was trying to protect Firill, and left.

Following Firill's marking as Hraesvelgr's mate, Mitsuki explained what she had discovered about Hraesvelgr's abilities and how they were connected to the manifestation of the spirit, but had been unable to come up with a concrete way to defeat it. As such, she was surprised when Yuu declared that he still had a trump card, but decided to trust him and leave the details of the plan to him. Just before Hraesvelgr's approach, Mitsuki expressed her concern over the fact that this battle was becoming similar to the one against Hekatonkheir three years ago, worrying that Yuu would disappear at the end of it again. However, Yuu reassured her that this would not happen. When Hraesvelgr appeared, Mitsuki lent her dark matter to Yuu so that he could construct the Anti-Dragon Armament Noah, which could scatter Hraesvelgr's Ether Wind. After Yuu hit it with consecutive shots by creating two more Noah turrets, Mitsuki ordered everyone to attack the now vulnerable Hraesvelgr, successfully destroying it. Following the conclusion of the battle, Mitsuki visited Yuu in his room, but was worried over his seemingly distant attitude.

Midgard's CarnivalEdit

V5 C2

Mitsuki in a kimono alongside the girls of Brynhildr Class

In Volume 5, Mitsuki was shown to be disgruntled over Yuu’s increased popularity among the students and Firill's affection for him. During Brynhildr Class' discussion about their theme for the upcoming school festival, Mitsuki was responsible for chairing the proceedings. After the class decided on a Japanese teahouse, Mitsuki also helped her classmates in honing their culinary skills. Two weeks later, Mitsuki was shocked to find out that both 'Green' Yggdrasil and Hekatonkheir had disappeared after engaging in battle.

On the first day of the festival, Mitsuki was surprised and angered at Yuu's reluctance to meet their parents, but was forced to let the matter drop when Lisa claimed he had promised her that they would tour the festival. The next day, Mitsuki was shocked when Lisa announced that she and Yuu would be a couple, but calmed down upon listening to the whole story and promised to help deceive Lisa's parents in order to postpone her engagement.

When Yggdrasil was reported to have invaded Midgard, Mitsuki joined the rest of her classmates and Charlotte in the command center in order to discover the Dragon's whereabouts. Upon discovering that Yggdrasil had taken Iris, Ren, Firill and Lisa's parents hostage, Mitsuki led the Dragon Subjugation Squad in an attempt to rescue them. Although the hostages were successfully liberated thanks to Yuu and Lisa, the Dragon Subjugation Squad was unable to harm Yggdrasil due to its interference with dark matter and machinery, until Iris destroyed the Dragon thanks to her newly-awakened ability to use Catastrophe. Following the conclusion of the battle, Mitsuki visited Yuu in the infirmary alongside her classmates and was alarmed when Lisa's father declared that he approved of Yuu as a prospective suitor for Lisa.

Emerald TempestEdit

In Volume 6, Mitsuki was dispatched to Asgard's First Laboratory in Japan alongside the rest of Brynhildr Class in order to participate in the plan against Yggdrasil. After being introduced to Kenya Miyazawa and witnessing Kili's assault on the lab, Mitsuki participated in the meeting where Kenya explained the true nature of Yggdrasil, as well as the countermeasure he had devised against it. Afterwards, she was interviewed by Kenya alongside Yuu, Tear and Iris due to her unique ability to create antimatter. Due to Yuu and Ren's inability to perform dark matter transfer effectively, it was decided that Brynhildr Class would visit an amusement park in order to improve the relationship between the two. During their visit, Mitsuki conspired with the rest so that Yuu and Ren could have some alone time at the Ferris wheel, but was jealous upon hearing Ren address Yuu as Onii-chan. Following Tear's brief kidnapping by Jeanne Hortensia, Mitsuki returned to the lab alongside everyone else.

V6 I8

Mitsuki upon discovering Yuu's secret

When Yggdrasil started extending its branches in order to expand its area of interference, the Dragon Subjugation Squad started attacking the branches in order to approach its main body, with Mitsuki pairing up with Firill. After Yuu's secret was exposed to everyone, Mitsuki was greatly shaken and started crying, calling herself useless for forcing him to make a deal with Yggdrasil in order to protect their hometown in the first place. She then stated that she had realized long ago that Yuu was hiding something desperately and asked him if he was keeping any other secrets, something which Yuu confirmed, but refused to elaborate upon. When Yuu proposed retreat, Mitsuki announced her resignation as captain of the Dragon Subjugation Squad and her intent to charge Yggdrasil in order to clear a path to its main body. However, she was stopped by Tear, who declared her intent to have the final modification performed on her horns by Kili. Thanks to Tear's new found abilities, the Dragon Subjugation Squad was able to approach Yggdrasil's main body and strike at it directly. Mitsuki then proceeded to join her classmates in transferring their thoughts to Yuu, enabling him to fire an enhanced shot from his Noah turret and further damage Yggdrasil's soul. Following the hijacking of Yggdrasil's core by Tear, Mitsuki accompanied everyone back to the lab.

Black NemesisEdit

In Volume 7, upon arriving at the Asgard lab alongside the rest of her classmates, Mitsuki was surprised to see that it was heavily damaged. After the issue of lodging was brought up, Mitsuki suggested that everyone could stay at her and Yuu's home. Upon arriving, Mitsuki proceeded to introduce everyone to her and Yuu's parents, while also explaining that she had been adopted into the Mononobe family after her parents passed away.

The following day, Mitsuki spotted Yuu and Iris kissing in a park. Although she tried to flee, she was restrained by Iris, whose words confused her. After Yuu explained to her the loss of his memories as a result of his deals with Yggdrasil, Mitsuki felt troubled and lost over the rapid developments, but reassured Yuu that, from her point of view, he had always been himself despite the loss of his memories. However, shortly after Yuu's memories were unblocked by Tear, 'Black' Vritra made a sudden appearance in her dragon form, before assuming the shape of a young girl in order to speak with Tear. Mitsuki then proceeded to escort her to her house alongside everyone else. After a brief discussion, it was decided that everyone would tour Nanato City in order to jog Yuu's memory. During the visit to the observation platform that Yuu and Mitsuki frequented as children, Mitsuki approached Yuu, asking him if he recalled their promise. She then confronted him over his feelings for Iris, claiming that the love that he felt for her was only at the level of family and that he should pursue a relationship with Iris. This resulted in an argument between her and Iris as one was trying to yield Yuu to the other, which ended when the rest of the class joined them. On the way back home, the group came across a battered Kili and an unconscious Jeanne, with Mitsuki noticing in shock that Kili's dragon mark had started changing color.

After bringing the two girls to Mitsuki's house, Mitsuki was surprised to hear that Yuu had encountered Kili before in their hometown. Upon learning that Kraken Zwei was approaching the town, as well as her being Miyako's child, Mitsuki was greatly disturbed. However, she assured Haruka and her classmates that she would perform her duties. Upon arriving at NIFL's base and being briefed by Haruka, Mitsuki set out to confront Kraken Zwei alongside Yuu, Iris, Ren and Ariella. However, upon noticing Zwei's human appearance and her resemblance to Miyako, Mitsuki was unable to bring herself to shoot her. Her second attempt in attacking resulted in her Fictional Armament disappearing due to her internal refusal to vanquish Zwei, forcing her to sit the rest of the battle out.

V7 I9

Mitsuki attempts to kiss Yuu

Following Zwei's imprisonment in a mithril-covered hole and the Dragon Subjugation Squad's return to base, Mitsuki was ordered by Haruka to rest in her room due to her evident physical and mental exhaustion. She was then approached by Yuu, who declared that she wouldn't allow her to fight Zwei again and would deal with the hybrid himself. Mitsuki then requested for Yuu to kiss her in order to realize that the one he truly loved was Iris. However, before they could go through with it, Mitsuki received an urgent message from Lisa, stating that Vritra was heading to their location with the intent of exterminating Mitsuki, since her antimatter projectile was the only effective weapon against Zwei. Mitsuki then proceeded to participate in the battle against Vritra's dragon stand-in. Following the stand-in's self-destruction, Mitsuki was lightly wounded by Vritra in her human form. However, she collapsed due to Vritra's poison, which was designed to put her to sleep for a couple of days. Shortly afterwards, her dragon mark started changing color as one of the girls who had participated in the battle against Kraken Zwei due to the hybrid's ability to mark multiple Ds as mates.

Amethyst RebirthEdit

In Volume 8, Mitsuki was out of commission due to Vritra's poison, which put her to sleep for the duration of the battle against Kraken Zwei. While Brynhildr Class was travelling back to Midgard, Mitsuki appeared before Yuu, revealing that her dragon mark had also been dyed in his color alongside the rest of the girls. She then got into a brief argument with Iris, trying once more to yield Yuu to her, which was interrupted by the demand of the rest of the girls for Yuu to take responsibility for marking them, prompting the two of them to realize how foolishly they had been acting.

Cerulean EngageEdit

In Volume 9, Mitsuki was contacted by Yuu, leading to her starting to question him about his daily life during his confinement in the principal's quarters. However, her terminal was snatched away by Firill and was passed around to the rest of the girls, who also wished to speak with Yuu, before finally returning to her. During NIFL's attempt to invade Midgard under the pretext of an inspection, Mitsuki was brought to Charlotte's underground cottage alongside the rest of Brynhildr Class, Kili, Jeanne, Shion and Vritra by Haruka in order to hide from NIFL. After everyone settled down, Mitsuki approached Yuu, stating that she had chosen to be the first to discuss about transforming into his kind with him. After assuring him that she was ready for it, Mitsuki requested from Yuu to have their discussion while taking a bath in the hot spring in an embarrassed tone.

V9 C1

Mitsuki transforms into Yuu's kind

While soaking in the hot spring, Mitsuki revealed to Yuu that she had kept her old house next to his because it was her dream that the two of them would live there after marrying and starting a family, before changing the subject. She then asked Yuu if he didn't feel burdened by the responsibility of selecting everyone as mates, stating that she didn't wish to make him feel even more tormented. After he assured her that this was not the case, Mitsuki requested for Yuu to change her. Before he could go through with it, however, she asked him to kiss her dragon mark, stating that it would be very romantic. After her transformation was complete, Mitsuki was escorted back to the cottage by Yuu in a woozy state. Following Ariella's defection to NIFL, Mitsuki prepared to head to the surface alongside the rest in order to combat NIFL and rescue Ariella, despite her apparent exhaustion.

Invisible SuccessorEdit

In Volume 10, Mitsuki joined the rest of Brynhildr Class in heading to Charlotte's office in order to protect her from NIFL's forces, brushing off Yuu's concerns about her obvious exhausted state. Upon arriving at Charlotte's office, Mitsuki was shocked alongside the rest to see her bleeding, but calmed down upon hearing Charlotte's reason for this. After Charlotte explained her plan and asked the girls of Brynhildr Class if they were afraid of her, Mitsuki stated that they would trust Yuu's judgement, while also remarking that the worst thing Charlotte had done was to steal underwear. Upon receiving news that Ariella was approaching from underground, Mitsuki joined Yuu, Kili, Ren, Iris and Tear in intercepting her. Although Ariella and Sleipnir's abnormal abilities made things hard for everyone, Mitsuki and the rest were able to subdue them thanks to Yuu’s newfound ability to share feelings and thoughts with his mates. Following Ariella's transformation into Yuu's kind, Mitsuki welcomed her back, while also requesting from her to write twenty repentance essays as punishment and demanding from Kili to also hand in repentance essays for her past transgressions. Upon seeing Ariella in a flustered state from Yuu's compliment, Mitsuki demanded that Yuu hand over ten repentance essays as well.

Following that confrontation, Mitsuki proceeded to head to the surface alongside the rest and was shocked to see that a blood mist had enveloped all of Midgard and had rendered everyone unconscious. Afterwards, the group joined up with Lisa and Firill and encountered Mica, who explained that the mist was a result of Charlotte losing control of her powers. Upon hearing the sound of an explosion coming from the front gate, Mitsuki rushed there along with everyone else to investigate and encountered Major Loki there, accompanied by two Hreidmars. After a brief discussion between him and Yuu, Mitsuki was urged by Yuu to flee along with the rest of the girls due to Loki's ability to kill anyone by thought alone.

While Yuu and Charlotte were struggling to control their Authorities, Mitsuki appeared before Yuu alongside the rest of Brynhildr Class, asking him to share Code Lost with them as Vritra had suggested to him. Mitsuki then proceeded to offer her dark matter to Yuu alongside the res
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Mitsuki is informed by Vritra that she is the host of the Ninth True Dragon

t of the girls in order for him to construct the Anti-Dragon Armament Abyss and get rid of the blood mist. When Babel Replica fired at Midgard, Mitsuki also offered her dark matter to Ariella alongside the others so that she could construct a shield to protect them while Tear headed out to disable the weapon. Following the conclusion of the battle, Mitsuki was anxious about the strange condition of her body, wondering if it was an after-effect of her transformation. After touching her dragon mark, she was horrified to see that her fingers briefly turned transparent and black. At that moment, she was approached by Vritra, who informed her that the Ninth True Dragon, the calamity which would destroy the world, was within her.

Prismatic GardenEdit

In Volume 11, after hearing Vritra's words, Mitsuki's body started changing. However, the process abruptly stopped, with Mitsuki having no recollection of what Vritra had just told her. When the time came for everyone to move to her dorm, Mitsuki thanked Charlotte for everything, while also stating she would watch over Yuu carefully in order to prevent him from approaching other girls. She also participated in the game that would decide who would get the room next to Yuu's, although she was swiftly eliminated, while also warning Yuu that he should quickly decide what sort of relationship he wished to form with everyone. That night, Mitsuki visited Yuu's room with the purpose of retrieving a toothbrush she had left there. After confessing that she had been using this room while Yuu was detained in Charlotte's quarters, Mitsuki indirectly asked for permission to keep using his room. When Yuu agreed, Mitsuki thanked him in a happy tone and left.

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Mitsuki and Shion prepare yakisoba

The following day, Mitsuki introduced Kili, Jeanne, Shion and Vritra along with the new students to the school assembly, admonishing Kili for her declaration that Yuu was hers. When Charlotte announced her intent to hold a festival, Mitsuki decided to have Brynhildr Class participate by helping with Haruka's yakisoba stall after Shion expressed interest in the festival. She then joined the rest of Brynhildr Class in learning how to make yakisoba during their barbecue party in the beach. While there, she and the rest of the girls mistakenly assumed that Yuu had a fetish for breasts due to Shion's misleading words. Upon witnessing Yuu with his face buried in Iris' chest, Mitsuki stated that she was both mad and jealous at the same time. She then urged Yuu to decide on her position and who the one dearest to him is. After leaving him, Mitsuki started berating herself for forcing Yuu to make a decision due to her own insecurities. Suddenly, she began feeling unwell and was urged by Vritra to rest.

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Mitsuki in her yukata

On the day of the festival, Mitsuki met with Yuu when her shift was over. After reminiscing about past events while walking on the beach, Mitsuki declared that she had always been in love with Yuu since they were children and that he was her most precious person. She was surprised when he in turn stated that she was also the one dearest to him. However, at that moment, Mitsuki recalled Vritra's words about Yuu's feelings being a result of his instinct as a Counterdragon and called herself worthless to him. Due to her agitation, the Ninth True Dragon started emerging from her body, but was suppressed by Yuu's Authority before it could consume her. After regaining consciousness, Mitsuki kept tearfully apologizing to Yuu, thinking that she had hurt his feelings.

Darkness DisasterEdit

In Volume 12, Mitsuki was brought back to the dormitory after collapsing from exhaustion, where the rest of Brynhildr Class was informed about her status as the host of the Ninth True Dragon by Yuu. When Charlotte notified everyone about the sudden appearance of unknown territories around the world along with that of the Fifth True Dragon 'Eternal Longevity' Bahamut, Mitsuki ordered everyone to prepare to set off after Tear announced her intent to complete Marduk as a means of transportation to get to the battlefield.

V12 I3

Mitsuki is forcefully stripped by Iris

Following the assembly of Midgard's entire student body, Mitsuki informed them of the situation and asked them to lend their dark matter to Yuu in order to construct Marduk. After the ship's completion, Brynhildr Class and Haruka set off for NIFL's first defensive line, with Mitsuki sharing a cabin with Iris. While Iris attempted to console her by stating that instinct was the source of all emotions, thus making Yuu's feelings for her genuine, Mitsuki claimed that something else was the source of her fear, but Iris interrupted her before she could finish her thoughts. Afterwards, she insisted that Mitsuki take a shower, attempting to forcefully strip her, much to Mitsuki's embarrassment. During the pre-operation briefing, Mitsuki was tasked with watching over Shion and Vritra during the battle, much to her chagrin. While watching over the sleeping Shion in her cabin and wrestling with her anxiety, the Ninth True Dragon spoke to Mitsuki by assuming Miyako's form, asking her if she was really fine with how things were and suggesting that the two of them realize Mituski's true wish together. However, thanks to Shion's and her own Code Neun, Mitsuki suppressed the Ninth True Dragon, although she was rattled by its words.

Following the operation's failure due to Catastrophe's insufficient output, Mitsuki participated in a discussion with Iris, Shion, Vritra and Yuu in an attempt to find a solution. There, Mitsuki pointed out that the Third Eye of Catastrophe was probably required to defeat Bahamut due to its enhanced output matching the True Dragon's massive size, which meant that Iris had to discover the location of her Authority in order to use its full power like Yuu had done before. When she was left alone with Shion, Mitsuki attempted to discover the location of Code Neun and was successful in doing so, figuring out its true nature. During the second operation against Bahamut, Mitsuki requested for Yuu to allow her to fight following the appearance of the Sixth True Dragon, 'Anomalous Dawn' Nyarlathotep, but he instead asked Shion to join him due to her insistence that her Authority was stronger and Mitsuki's state. After both True Dragons were vanquished, the darkness spreading from Bahamut's trail attempted to consume Marduk, but was absorbed by Mitsuki along with that of two out of the four unknown territories.

UnlimitedFafnir v12 249

Mitsuki attacks Iris

In the aftermath of the battle, Mitsuki was once again approached by the Ninth True Dragon, who relayed Vritra's plan of sacrificing Mitsuki to destroy the ninth calamity and asked her if she was fine with that. In response, Mitsuki stated that the True Dragon didn't understand Yuu at all, but thanks to its words, she now knew what she had to do. Just as Mitsuki exited her cabin, she bumped into Iris. Taking advantage of this opportunity, Mitsuki expressed her envy for her and revealed that what she truly feared was that Yuu's feelings for her would fade away if they were to defeat the Ninth True Dragon. After stating that Yuu no longer loving her was a fate worse than death for her, Mitsuki declared that the outcome everyone was striving for was not the one she wished for, making her everyone's enemy. She then proceeded to attack Iris and damage Marduk. Mitsuki then showed herself in front of Yuu and Vritra, announcing her intent to deal with the remaining two unknown territories on her own with the help of the Ninth True Dragon, who assumed Miyako's form completely. When Yuu attempted to stop her, Mitsuki coldly stated that he should see to Iris, whom she had left in her cabin. After asking Yuu to leave everything to her, she took off alongside the Ninth True Dragon.

Powers and AbilitiesEdit

Dark Matter Generation: Like every D, Mitsuki can generate and manipulate dark matter, transmuting it into various substances.

  • Brionac: Mitsuki's Fictional Armament, which takes the form of a rainbow-colored bow and enables her to launch a number of different attacks by shooting arrow-shaped Dark Matter.
    • Adhesive restraint: Mitsuki fires an an arrow that transmutes into an adhesive net.
    • First Arrow - Forked Wind: Mitsuki shoots an arrow to compress the air around her, generating a large number of wind arrows.
    • Second Arrow - Night Blaze: Mitsuki generates an arrow made up of heat energy.
    • Third Arrow - Lunar Eater: While the exact details of this arrow are unclear, it was shown to be able to pulverize the branches of Yggdrasil.
    • Terminating Arrow - Last Quark: During the battle against Kraken, Mitsuki obtained its Authority, Code Sechs, which she uses in tandem with her arrows. This enables her to fire an antimatter projectile capable of destroying any form of matter through an annihilation reaction with ease. According to Vritra, Mitsuki did not exhibit signs of transforming into a Counterdragon because she had not inherited the full Authority.
  • Flight: Mitsuki is capable of flying by using air to levitate from the ground.

Code Lost: In Volume 10, Mitsuki acquired a part of Code Lost after Yuu split the scrapped Authority between his mates.

Code Neun: As one of Yuu's mates, Mitsuki possesses his Authority, Code Neun. Although the true nature of this Authority and its full capabilities are still unknown, it was shown to be capable of supressing the Ninth True Dragon's End Matter. Unlike the other users, Mitsuki has fully mastered Code Neun as of Volume 12 due to her discovery of its location and true nature.

Archery Proficiency: Having a bow as her Fictional Armament, Mitsuki is shown to have incredible aptitude for archery, capable of hitting her targets on the mark with her arrows.


Yuu MononobeEdit

Mitsuki's childhood friend and non-blood related older brother, whom she promised to marry when they were kids and kissed him on the lips as a sign of their engagement. Mitsuki treasures Yuu very much, evident from the fact that she outed herself as a D in the hope that the two would be reunited in Midgard. Even when she found out that Yuu was not there, she motivated herself to work hard in order to discover his whereabouts. Although she was reluctant to pursue him due to the guilt she felt over Miyako's death, she declared that she would not give up on him after Basilisk's defeat. She is especially strict with him and constantly warns him not to sexually harass the other girls with his comments, something which she always calls him out for. Mitsuki has also exhibited jealousy whenever a girl comes close to Yuu. When she found out that he and Iris had feelings for each other, she tried to distance herself, only to get into arguments with Iris, who was trying to yield Yuu to her. Mitsuki was shown to be very happy when Yuu marked her as a mate and did not hesitate at all to complete the process by having Yuu kiss her dragon mark. After that, she showed no hesitation in expressing her affection and love for him more openly. But upon learning about the Ninth Calamity sealed within her and that Yuu's feelings for her might be a result of his instinct as a Counterdragon, she began worrying about whether his feelings for her would remain the same after the calamity was dealt with.

Miyako ShinomiyaEdit

During their stay at Midgard, Miyako was Mitsuki's roommate and best friend. The two would hang out together most of the time, with Miyako sometimes comforting Mitsuki and giving her confidence when she was down. When 'Purple' Kraken attacked Midgard, Mitsuki was devastated when Miyako turned into a Kraken as well and she was forced to kill her, causing her a great amount of guilt for a long time. It's implied that Miyako had romantic feelings towards Mitsuki, something which she's seemingly unaware of.

Lisa HighwalkerEdit

The two are classmates and became great friends when Mitsuki transferred to Midgard. However, their relationship soured after Miyako's death, an act which Lisa condemned Mitsuki for. In truth, however, Lisa did not resent Mitsuki at all and only acted like this in order to alleviate Mitsuki's guilt, since she craved punishment for her actions. Eventually, thanks to Yuu's intervention, the two girls reconciled and became friends once again.

Haruka ShinomiyaEdit

Haruka is a former classmate of Mitsuki, as well as her predecessor in the position of Student Council President and Captain of the Counter-Dragon Squad, and is currently the homeroom teacher of Brynhildr Class. Mitsuki looks up to Haruka and the two have a formal relationship.

Iris FreyjaEdit

Mitsuki's classmate and close friend. They are both aware of each other's romantic feelings for Yuu and both were willing to put aside their feelings for the other's sake. However, this no longer seems to be the case since both of them have been marked as Yuu's mates.

Shion Zwei ShinomiyaEdit

Mitsuki cares greatly for Shion due to the fact that she is her late best friend's daughter. She has been shown going out of her way in order to accommodate her wishes, like participating in the school festival.

Kai and Yoshimi MononobeEdit

Mitsuki's adoptive parents, who took her in after her birth parents died in an accident. Although she was upset about it at first, she calmed down after Yuu assured her that they could still get married as they had promised. Afterwards, Mitsuki began to see them as her real parents and even called them so. Even after transferring to Midgard, she still contacted them every now and then.


  • Brionac is named after the lance used by the Celt god of light, Lugh.
  • Mitsuki has a tendency to number her moves, probably as a homage to Haruka Shinomiya.
  • Due to the fact that Mitsuki was able to generate antimatter before killing either Kraken, it is possible that Miyako somehow granted her that power after being dragonified.
  • Mitsuki has a slight dislike for spicy foods.
  • Mitsuki has been shown to have a minor breast complex in Volume 5.
  • Mitsuki is one of the four only girls to have kissed Yuu on the lips so far.
    • She is also the first girl to have kissed Yuu.