MikaYuu

"Yuu...I love you."

- Mikaela's last words to Yuichiro

MikaYuu is the slash ship between Mikaela Hyakuya and Yuichiro Hyakuya from the Seraph of the End fandom.

Canon
Mika and Yu meet on Christmas Day 2012, the same day a virus that wiped out the majority of the world's population was diffused. They, like the other children of the orphanage, are taken by the vampires and transferred to the vampire city of Sanguinem, where they are treated like livestock. Throughout their years in Sanguinem, the children of the Hyakuya Orphanage slowly become a found family, relying on each other for companionship and support. From the first chapter of the anime manga/episode, Mika and Yu are shown to be close. Mika tends to create excuses for Yu to avoid conflict with vampires so he can keep him safe and is very sympathetic to Yu. It was Mika who arranged for Yu and all the other children from the orphanage to escape, but Ferid discovered them and killed all the children except Yu and left Mika critically injured. When Yu tried to save him he pushed him away telling him to escape. However, Mika was transformed into an incomplete vampire by Krul after Yu had escaped.

Yu joins the Moon Demon Company on the other side of the war. He swears that he would take revenge on the vampires who killed his family, but of all the members of his family, what he most often had in mind was Mika, even dreaming of him several times. Four years later, on the battlefield, Yu discovers that Mika became a vampire. Yu, shocked by that information, searches for a method to turn back Mika into a human, but in vain. When they met for the first time Mika took Yu in his arms and once alone asked to him abandon everything and escape with him, soon after Yu turns into a demon. In his form as a Yu demon, he loses control and attacks Shinoa, but Mika defends her by letting the sword stab him instead, saying that Yu wouldn't want to kill a human and that he would never forgive himself. When Yu returns to normal, Mika is forced away by Ferid. When Yu wakes up he swears along with Mika (obviously at a distance but at the same time) that they would save each other; Mika would save Yu from the humans who he believed were using him, and Yu would save Mika from the vampires who he believed were keeping him against his will.

Next, they meet again on the battlefield, here Mika sees Yu passed out on Kimizuki’s shoulder and faces the demonic army to reach Yu. Thanks to the team of Yu who protects him, he manages to escape with Yu and bring him to safety; however Mika is wounded and at first, tries to drink the blood of Yu when the latter regains consciousness, Yu consents to it and hugs Mika telling him that he is sorry to have abandoned him and that it is his fault, however, Mika comes to his senses before biting Yu and apologizes to him. Mika claims to have something very important to say to Yu, but Yu says he won’t listen until Mika agrees to drink his blood so he can live. This is important, because although Yu claims to hate all vampires, he begs Mika to become a vampire to save his life. This shows how much Yu cares about Mika. So, Yu cut his arm, trying to tempt Mika to drink his blood. Mika tries to resist but eventually bites his neck, which does not seem to hurt Yu (the official fanbook has confirmed that when a vampire bites a human, both feel good). Yu then tells him, "Welcome back, Mika". After returning to full health, Mika claims that he would never use Yu, but he replies that although he said so he drank his blood, but immediately after caresses his cheek and say that he doesn't care about the blood. Mika asks Yu to flee with him and live together in a place away from humans and vampires. Yu, however, tells Mika that a peaceful place in their world does not exist and that if they wanted to escape, they should first ask his teammates for help. When Mika agrees to save Shinoa’s squad, Yu is happy and hugs him, and the two go hand in hand while on the way to go aid Shinoa's squad.

After Mika's escape he swore that he would watch over Yu being the only one he trusted, on the battlefield Mika has no interest in himself and his only thought is to keep Yu safe. Yu often offers his blood to Mika when he is reluctant to drink the blood of his teammates, but Mika prefers not because he is afraid of hurting him. In chapter 55, Mika holds Yuu's hand to comfort him after seeing the departed members of their family. Mika also explains to Yu’s teammates that since he became a complete vampire he feels that his human emotions are disappearing, but only his feelings for Yu have not changed. Mika is willing to do anything to protect Yu, even saying that what Guren did to Yu for him is enough to kill him. He knows that Yu would hate him if he did but he doesn't care, anyway whenever Mika gets too threatening towards Guren Yu stops him. When they are alone Yu asks Mika if his heart is beating, Mika tells him that he could find out for himself, then Yu puts a hand on his chest and is surprised that it doesn't beat. Since Yu is not totally human, he tells Mika that he will find a way to make them both human, but Mika is doubtful about that.

In chapter 85, the past Mika from ancient Greece was shown for the first time. When Yuu sees everyone gathering around Mika's coffin, he wonders what's there. Noya shows Mika to Yu and Yu calls Mika a "beautiful girl".

In chapter 86, while on the run from Guren and his demons, Yu is addressed by Mahiru, who asks him if he's found a new reason to live. He contemplates, remembering that moment, and takes Mika's hand, telling Mahiru and Mika, "I have a reason to live. I have you, Mika." Mika is happy to hear Yu call him that. It is also noteworthy that when Yuu in childhood asked Mahiru what the reason to life, she replied that it was love and said that her meaning of life was Guren, whom she loves romantically. Later, Mika is wounded in the fight between Guren, Mahiru, and Noya. Yu picks up Mika and tells him to drink his blood, Mika does it and Yuu says it feels strangely good to have his blood sucked.

In chapter 89 of the manga, Mika suffers a grave injury protecting Yu from Guren. Mika tells Yu to not worry, and that he would keep Yu safe. In chapter 90, as Mika is dying in Yu's arms, Yu is desperate to keep Mika alive, saying "Anybody!! God! The Devil! I don't care who it is! You can even kill me! Just save Mika!". He is then transported into his subconsciousness, where Asuramaru is. Asuramaru asks Yu what he wants because demons are supposed to help grant their human's deepest desires. Yu responds, saying how he doesn't want to be alone, and that he wishes that he could disappear because he feels useless. He asks Asuramaru to kill him. Asuramaru says, "From the start, you couldn't find a reason to live. You smiled and laughed, but it was empty. If someone wasn't right there, telling you they liked you, you just didn't know why you should exist. But that someone always dies. Now you can't go on living anymore". Asuramaru reminds Yu that Mika loved him, even to the point of giving his life for him to protect him, Asuramaru to refer to Mika's love for Yu uses the Japanese word "aishiteru", which is used to indicate a very strong love. Asuramaru forces Yu to look at Mika, to watch him die so that he has a reason to continue living. Mika sees Yu crying and tries to tell him not to cry. Yu screams to him, "Don't leave me! I don't want to be alone!", implying that he feels alone without Mika despite having other friends. With his final breath, Mika says, "Yu... I love you," using the Japanese words, "daisuki da yo" which is usually only used in a romantic context. Yu screams out his name, reaching out to him, but Mika explodes. The official description of chapter 90 from Kagami said: "For Yuu, whom his parents called a demon, Mikaela, who loved him, became his reason to life. If Mikaela dies, Yuu will no longer be able to live".

In chapter 93, Mika is in a world where all the orphanage kids are alive and everyone is still young. While getting ready for bed, A twelve-year-old dream Yu takes Mika's hands, telling him he doesn't have to be scared, and that Yu will always be there. He comforts Mika's guilt of not being able to protect everyone, saying, "That's fine. We'll still be together. For a thousand years. Ten thousand years. No...forever". Mika realizes that it is a dream, and tells dream Yu that. Dream Yu tells Mika to accept that this is his greatest desire. Dream Yu tells Mika that if he stays here, his greatest desire could be possible, and he could stay with Yu forever. Mika gives in, and wings sprout from his back.

In Chapter 94, Yu tries to save Mika, who seems to now be a demon but is stopped by Krul. Seeing that Krul is trying to separate him from Mika, he treats her rudely and tells her to shut up, despite the fact that she is the third progenitor of the vampires. She explains to him that Mika can be saved but if Yu approaches Mika now he will kill him. Yu then is happy and asks Mika to wait for him, promises him that he will save him and that no matter what part of the world he would be in, Yu would find him and save him.

In chapter 96, when Krul goes missing, Yuu's only worry is that he can't save Mika now. He also says that Krul is their friend because she saved Mika and asks her to help him save Mika at the first opportunity. Yu has a flashback. In his flashback, he tells Guren, "I swear I'm gonna kill all the vampires, because they killed MIka!", which shows how his motivation for wanting revenge was because of Mika. Then, Krul has a flashback of her training Mika. In that flashback, she asks Mika in her head, "Do you want to save Yu that badly? Is your mind so full of thoughts of him... that it drives you to this insanity?". In the present time, Yu asks Krul to tell him how to save Mika. In the English translation, Krul then says to Yu, "If you really want to rescue Mikaela that badly, then prove it. Stop fooling around and show me that you truly, sincerely want it." She then thinks in her head, "Otherwise, it wouldn't be fair for what he went through". However, the meaning of the Italian translation (that is also directly translated from Japanese) is closer to "Otherwise, the boy's feelings will not be reciprocated". Hearing that, Yu bows to her and begs her to tell him how to save Mika, telling her that he values Mika's life more than his own. After he tells Krul this, Krul thinks "Ahh. Yes... He has it just as badly", indicating how his feelings for Mika are as strong as Mika's feelings for him. When Yuu kneels, he assumes the Dogeza pose. Previously, this was considered a posture in which a person shows maximum respect for another and asks for something. But in modern Japan, this is considered a humiliation of oneself. This is also notable considering that as a child, Yuu promised to kill Krul and all vampires, but kneeled before their queen for Mika, thus humiliating himself.

Further, when Guren appears, he says that he will save Mika, which undoubtedly pleases and encourages Yuu. When Yuu hears that Asuramaru is an enemy and Mika is in danger, he tries to call Asuramaru, but realizing that he does not answer, Yuu says that he will not forgive Asuramaru if he hurts Mika, even if he has his own goals.

In chapter 101 Asuramaru enters the illusionary world of Mika and forces him to kill his family while Mika continues to apologize saying that it is all his fault since his "greatest desire" was to be blamed for their deaths. At one point, in desperation, he screams out Yu's name asking for help (even though demons supposedly lose their memories after transformation). Yu hears Mika's call for him, and tells his teammates that Mika is in danger and he must immediately go to rescue him, going as far as to say that he will "run over" anybody who get in his way. Although Mika seems to keep his memories for now, Guren reminds Yu that Mika is now a demon and if he can get the upper hand over Yu, he could posses him. Yu retorts that this way Mika could continue living, but Guren replies that Mika would never want to live if it meant killing Yu, same way Yu couldn't live if Mika died. He understands what Guren means and after informing the others, goes to save Mika. An interesting thing to note here is that when Yu is about to leave, Shinoa says she'll cry if Yu died. This is a direct parallel to Yu saying he'll cry if Mika dies in chapter 36. Since Shinoa's feelings for Yu are blatantly romantic, the parallel shows that Yu's feelings for Mika have romantic undertones as well. Once Yu enters the dream in which Mika is stuck, he finds Asuramaru - along with the other demons - and asks him "What're you picking on my Mika for? Want me to kill you?" (note the use of "my"). Soon after, he injures the demon, and yells at Mika that he's here to save him.

In chapter 102 Yu reaches Mikaela and tells him that he has come to save him, but before Yu can take him he is taken away by the other 2 demons and while Asuramaru tries to posses Yu. In one of the dialogues with Asuramaru, he says that his main desire is to save Mika, to which Asuramaru replies that this is a lie and he has another desire. Immediately Asuramaru says that this desire is related to Mika, he asks Yu why he is so fixated on Mika and what desire he has that drives him be so fixated on Mika. But Yu doesn't answer that question. After defeating all the demons Yu approaches Mikaela (who continues to cry, but does not attack him) and tells him that even if the world ends tomorrow, he will still save him.

In chapter 103 Yu wakes up in the place where Mika "come back to him", that is, in the shop where Mika became a complete vampire. When they meet Mika asks Yu why he knows his name, then Yu says that Mika must remember him if he chose a place like this (the shop). Mika keep saying to not remember him, but he says that he is a demon and therefore he must posses Yu. At this point Yu remembers the Guren's words in chapter 101 and tells Mika that if he did such a thing he would surely cry later, so he won't let him do it and he will subdue him. Soon after, the two being to fight. After combat Mika sees a coliseum circling their location. Many dark orbs are in the air and Mikaela wonders if this is inside his heart, or Yu's, and who exactly he is.

In chapter 104, Mika and Yuu fight each other. At one point, Yuu recalls a dialogue with Guren, who says that the only way to save Mika is to attack him, otherwise Shikama Doji will find him and the plan will fail. Because of these words, Yuu says that he will break Mika's heart, although he doesn't want to do it, Mika attacks faster. Mika sees in Yuu's heart his greatest fear: the death of his entire family. Mika remembers that his name is Yuu-chan and that he wants to save him, but Yuu attacks him back. Yuu sees the same fears in Mika's heart. Yuu concludes that he and Mika share a common fear and dream. Mika calls Yuichiro "Yuu-chan" and Yuu thinks Mika remembered him, but this turns out to be wrong. Yuu says he will save Mika and make him a human, but Mika also decides to save Yuu. They speak in unison about their desire to save each other. They fight again, but Mika is faster and he cuts off Yuu's head. He enters Yuu's heart and takes the form of what Yuu desires most. Mika becomes a version of himself, but as a 16 year old human. In Yuu's heart, there is only darkness and Mika who glows, as well as a strange eye that is watching Mika. This shows that there is only darkness in Yuu's heart, but Mika is the only one there. Yuu's greatest desire it's Mika, which he himself is watching. Apart from this, there are also many parallels in the chapter with past chapters. For example, when Yuu and Mika talk about their desire to save each other in unison, it parallels Chapter 15, where they also promised to save each other. The cover of the chapter that Yuu give hands to Mika as a child is a parallel to the memory where Mika give hands to Yuu as a child. The moment Yuu pierces Mika with his sword is similar to the moment from the end of Chapter 12 when they rejoined.

In chapter 106, Mika continues her journey through Yuu's heart. He sees that the large eye inside Yuu is not hostile, but rather friendly. Touching her eye, Mika travels to the past and sees a small clone of Yuu. Yuu goes to the coffin in which Mikaela, Shikama's child, lies, and tries to constantly wake him up (this moment is also shown in chapter 105). To Noya's words that Mika is dead, Yuu says that he will wake Mika up, because that's what he was made for. This continues until Shikama attacks Mika and, being in danger, he hears Yuu calling for him. Yuu tells Mika to become his demon so that together they can devour each other and save themselves. Mika agrees to become Yuu's demon.

In chapter 107, Yuu continues to tell Mika to become his demon and asks Mika to call his name from the bottom of her heart. Mika gets into Yuu's heart again and talks to him. Seeing that Mika still doesn't remember him, Yuu gets upset. However, Mika says that she can work with Yuu, and Yuu says that together they can defeat Shikama, which Mika doubts. Mika talks about what she saw in the past, but Yuu doesn't remember it. Despite this, Yuu says that he is only willing to die if it will save Mika. To Mika's bewilderment, Yuu replies that he only remembers the last 16 years, which are related to Yuu trying to survive for Mika. Yuu says the only thing that matters to him right now is that they are both alive, and Mika says he feels the same way. Yuu extends her hand to Mika and says that their last 16 years are important to them and Mika agrees. Yuu tells Mika to take his hand so they can be together. But Mika still doubts, to which Yuu tells Mika about their family. Mika finally becomes Yuu's demon, and while saying "Mikaela", Yuu uses him to attack Shikama.

In chapter 108, Mika assumes an already new demon form of herself as a teenager due to Yuu's wishes. He tells Yuu about this and Yuu feels Mika devour his desires. They both want to talk about their future, but they feel that now is not the time and they must defeat Shikama. Yuu extends his hand to Mika, who becomes a sword, which surprises Yuu. Together they attack Shikama using various attacks. Yuu also mentions that since Mika became his demon, he feels very good and feels like he can do anything to him.

In chapter 109, when the angels appear, they are excited about what it is and Mika assumes that the answer is somewhere in Yuu. Yuu is surprised by this and Mika says that he still hasn't regained his memories. But Mika remembers part of the past with Yuu and brings some of the memories back to him, which pleases Yuu. After Mika sees Yuu's memories of Guren, he gets mad at Yuu for trying to die without him. Yuu is surprised that Mika was watching his memories and says that it was difficult and lonely for him to live without Mika, but then he mentions again that he survived to meet Mika. They decide to return to reality and, holding hands, they promise to protect each other.

In chapter 110, Yuu tries to call Mika when he is looking at the sun, and is surprised that Mika doesn't respond, so she calls him "Mikapoo" (puppy), which angers Mika. Mika reveals that he is gradually regaining his memories, which surprises Yuu as he thought Mika had fully regained his memories. Yuu asks if Mika can read his thoughts, and after a positive response, he is encouraged to have Mika look at his thoughts. But seeing the unpleasant scene with the toilet there, he only gets mad at Yuu. Yuu again asks Mika to look at his thoughts but sees that he cannot see due to Yuu's closed heart. Yuu says he did this with Asuramaru, but with Mika, he doesn't mind at all if Mika possesses him, but Mika doesn't want that. Yuu wants to work with Mika on a completely different level and Mika says that Yuu has grown up. Seeing that the main players are gathering, Mika decides to stay behind to protect Yuu.

In chapter 111, Mika and Yuu are on the road with the others. Seeing Yuu having fun, Mika gets mad at him and reminds him of the situation they're in. Mika says that Guren and the others are using him and Yuu, but Yuu reassures Mika that he has a plan and asks Mika to wait. After Guren doesn't answer Yuu's questions, Yuu uses Mika's power against Guren. Hearing that Guren's attacks are poisoning Mika, Yuu looks upset. Yuu also says that he feels happy about fighting Guren and Mika feels his desires. By absorbing Yuu's desires, Mika gives him more strength and Yuu says that together they can become even more powerful and together they fight against Guren also in chapter 112.

In chapter 113, a flashback from Greece is shown again when little Yuu came to Mika's coffin and tried to wake him up. When Shikama arrives, Yuu says that he wants to wake Mika up and play with him as it's his mission. Flashbacks to Shikama's stories, Yuu says that he is a prince and Mika is a princess that he must wake up. Yuu also says that he can kiss Mika to wake him up like in the fairy tales, but Shikama refuses to him, which makes Yuu upset. When Shikama wants to leave, Yuu tells him about Mika talking to him, which surprises Shikama. To hear Mika's every word, Yuu puts his ear to the coffin, so he doesn't get bored with Mika. Seeing this, Shikama says that Yuu definitely loves Mika (was translated into English as "cares") and Yuu says that Mika is very nice. Shikama offers Yuu to get Mika back and Yuu promises to help him. While continuing to go in the truck in the present, Yuu comforts Mika when he gets mad at Guren's words. When Yuu does the "family circle" again, he invites Mika to join, but he refuses.

In chapter 114, Mika and Yuu travel with the others to Akihabara, where they see the corpses of Akane and the others. After learning the price of resurrection, Yuu wonders how it works since Mika is a demon, but Guren replies that Yuu is the only one whose goal is different. Seeing Yuu's surprised look, Guren explains that Mika is not a human, but the child of Shikama Douji, so the price for saving him is the same as for all of humanity. Guren tells Yuu that he must choose between the whole world and Mika one. Guren tries his best to convince Yuu and even says that if he chooses Mika, then he will become their enemy. Mika also says that Yuu should choose the children, but Yuu chooses Mika anyway.

In chapter 115, in order to protect Mika, Yuu begins to confront Guren and his team. Mika tries to convince Yuu to stop, but Yuu only tells him to shut up. Seeing Yuu's actions, Mika gets mad at him saying that disgusting desires are growing in Yuu. Mika questions who Yuu's enemy is and Mika sees that it is a squad. Reminding Yuu that they are his family, Yuu says that Mika is his family. Mika replies that he is dead, but Yuu says she wants him back. Mika says that Yuu can't have everything and that it's only him against all of humanity, but Yuu says that he doesn't care about humanity. Mika desperately tries to convince Yuu to remind him of Akane and the others, what Guren went through fighting against Shikama and Yuu begins to cry. Yuu states that it is impossible for him to give up Mika. Mika says that Yuu can refuse him and reminds them of how they promised to save everyone from vampires when they were kids. Mika also starts to cry and says that while Yuu was with him, he could do anything, but he screwed up and the others died. Mika expresses her pain about being hurt by life, so he wants Yuu to save his heart. Mika asks Yuu so that together they can return Akane and the children. Hearing this, Yuu is even more confused and says it's not fair. Hearing Yuu talk about his wish to die, Mika says that they will all die and sooner or later he and Yuu will be together in heaven. Mika extends her hand to Yuu and tells him to make the right choice and then they will be together forever. Calming down, he takes Mika's hand and says he will make a choice. However, it turns out that Yuu tricked Mika to take his power and saving him, which surprises Mika. To save Mika, Yuu uses a lot of his power, what can drive him crazy, and actually tries to escape with Mika. Seeing that he still lacks the strength to escape, he asks Asuramara for help.

In Chapter 116, Yuu still asks Asuramaru to give him the strength to save Mika, which causes Yuu to lose control of himself. Asuramaru reminds Yuu that Mika doesn't want this and that Yuu also doesn't want to go insane because he won't save Mika then, but Yuu still asks for more power out of desperation.

In Chapter 117, Yuu continues to fight against Asuramaru in order to gain power and save Mika. When the situation gets out of hand, Yuu talks about saving everyone, including Krul, to get Asuramaru to believe him, but he immediately says "You only want to save Mikaela", implying that Yuu is lying about the others being important to him. Yuu continues to convince Asuramaru, but Asuramaru deduces "From the start, you've only ever had eyes for Mikaela", which confirms that Yu only cares about Mika. The phrase "had eyes for someone" has a romantic connotation and means that you are romantically interested in this person and devoted to him. Asuramaru also remembers that Yu was looking at Mikaela in Greece. When Yu says he will save Krul, Asuramaru tells him to go save Mikaela and not get in his way. During the battle, Yu always uses Mika's power, but at one point, when Asuramaru wounds Yu, he notices that Mika doesn't heal him. Yu realizes that Mika isn't helping him, and Asuramaru confirms this by saying that Mika wants Yu to lose. Asuramaru also thinks Yu is manipulating by Shikama, but Yu denies it. Asuramaru also says that Mika wants to die and Yu should let him go, but Yu doesn't change his attitude towards Mika in any way and in response to this Yu only says "I'm not going to give up on Mikaela". Asuramaru says that this could cause Yu to die, but Yu replies "I won't give up until i die... no, i won't give up even if I die", implying that he will fight for Mika until the very end.

Fanon
Yuichiro's name is only spelled with one u, and his nickname in the English translation of the manga follows this pattern (Yu); however the ship name uses Yuu (ゆう), the Japanese Hiragana spelling of his nick name.

There is a small amount of fan resistance to the pairing, due to both boys being placed in the same orphanage and staying in the same family unit. However, Yu spent the least amount of time as a member of the Hyakuya unit, arriving at the orphanage the day of the vampire attack, which meant he only stayed with Mika in the orphanage for mere hours. After that, they only stayed together for four years until the escape from Sanguinem. Before she died, Akane, another member of the Hyakuya orphanage, has been stated to have a crush on Mika in the light novels, so that proves how members of the Hyakuya orphanage don't think of each other as literal blood-related family.

Those against the ship also claim that they think of each other as brothers, but this is not true, as it was never stated anywhere in the manga, anime, nor the light novels that they think of each other as brothers. Although they call each other family, Yu also calls just about everyone he knows "family". Also, in Guren's squad, they also call each other family, and almost everyone in Guren's squad has a crush on Guren, which also shows that calling other family doesn't mean that you think of them as literal blood-related family.

On AO3, MikaYuu is the most written ship in the Owari No Seraph/Seraph of the End tag. It is Mikaela's most written ship as well as Yuichiro's. The ship also has over 2000 works on its Pixiv tag.

The fandom seems to be the most active on Twitter, as other social media platforms (such as Instagram, Reddit, or Youtube) tend to have people that actively antiship the ship.

The majority of fans ship MikaYuu (usually along with MitsuNoa (Mitsuba x Shinoa), KimiYoi (Kimizuki x Yoichi), and GureShin (Guren, x Shinya). But, there are also rivalships, the most popular being YuuNoa (Yuu x Shinoa). Other popular Yuu ships include KimiYuu (Kimizuki x Yuu), YuuYoi (Yuu x Yoichi), and MitsuYuu (Mitsuba x Yuu). Popular Mika pairings other than MikaYuu are MikaKrul (Mika x Krul) and MikaNoa (Mika x Shinoa).

Fandom
FAN FICTION
 * Michaela/Yuichiro tag on FanFiction.Net
 * Michaela/Yuichiro tag on FanFiction.Net

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Trivia

 * Mikaela's birth surname is Shindo, while Yuichiro's birth surname is Amane.
 * Mika's favorite color is green, which happens to be Yu's eye color.
 * Although the reason he gave was because it was the color of the sky, Yu's favorite color is blue, which happens to also be Mika's natural eye color.
 * In the official fanbook 108, it is revealed how Mika's favorite phrase is "Yuu-chan" and that since he turned into a vampire, he has only lived in order to reunite with him.
 * Mika has said "Yuu-chan" 72 times in the first season.
 * Mika is shown crying only for Yu, or at least for thing that concern him.
 * The opening song of the first season, X.U, is about Yu talking to Mika and the ending song of the same season, scaPEGoat, is Mika responding to Yu.
 * The opening song for the second season, Two Souls Towards the Truth, is from both of Mika and Yu's perspectives and it is about them while the ending song is about Guren and Mahiru.
 * Mika was the first vampire shown to bite Yu, and Yu was the first human that Mika drank blood from.
 * Funimation has stated that they shipped MikaYuu, even including it on their top ten OTP list.
 * The description written for MikaYuu was "These two will go to the end of the world to save one another. Bromance? Nah bro, this is pure romance! From childhood friends to caught on opposite sides, they still found a way to be together, caring only for one another’s happiness. Also, Yuu offered to be Mika’s source for blood! How romantic is that?"
 * In the summary for Chapter 94 on the official Shounen Jump twitter, Mika was called "Yu's beloved".
 * Mika and Yu have been shown blushing at each other many times.
 * When asked about the nature of Mika and Yu's relationship and if it would be romantic in 2015, the author (Kagami), aww'd and said that it was up to perspective.
 * In the spin-off manga, Serapucchi, there were many chapters that hinted romance between Mika and Yu. One such moment is in a chapter where Yu is transported into a dating sim, but he couldn't win anyone over. However, when Mika appeared, he achieved a happy ending instantly even though Mika was supposed to be a hidden character that was difficult to conquer.
 * There are many Valentine's day official arts of the two of them. In general, most Owari no Seraph official arts are just of the two of them.
 * In the Owari no Seraph game, Yu tells Mika how he wants to gather the orphan children in the world and raise them with him.
 * Kagami has retweeted Mikayuu fanart soon after the release of chapter 90 (Mika's confession).
 * In a 2018 Jump Festa Interview, Kagami said that he was inspired by Go Nagai's Devilman series
 * The main characters in the Devilman series are Ryo and Akira, and Mika and Yuu seems to be similar to them. Ryo is blond and Akira has black hair, just like Mika and Yu. The two pairings are both childhood best friends. In the Devilman series, it is confirmed that Ryo has romantic feelings for Akira, just like how Mika has romantic feelings for Yu. Ryo also has an alternate persona as Satan, and form as Satan is intersex that has an appearance of an angel with six wings. Mika is a seraph, and it is shown in chapter 93 that he also has six wings. Mika's full name is Mikaela, which is a more feminine version of the masculine name Micheal. Although Mika is male, there is a scene from the Ancient Greece period where his body is lying in a coffin, and Yu mistakes it for female and calls him "a pretty girl".
 * The best-selling volume of the Owari no Seraph manga is volume 22, which contains chapters 90 to 94. Chapter 90 had Mika's confession, and chapter 93 showed how Mika's greatest desire is to be able to stay with Yu and to stay happy with him forever. Both moments are major Mikayuu moments that are very important to Mikayuu fans. The volume sold so well that it even made it into the top ten manga sales ranking in the second week of October 2020.
 * In this four-part interview (translation), it is revealed how the directer of the anime thought that Mika and Yuu were similar to Romeo and Juliet when he was reading the manga.
 * This was further confirmed by Kagami himself, who replied, “You said, “Yuichiro and Mikaela are like Romeo and Juliet.” Even if the two are separated, the central axis of the manga is that they meet dramatically.” Kagami also mentions that Owari no Seraph is a story about Yu and Mika as well as their fate together.
 * In this interview with Ono Kensho (Mika's voice actor), he says "To Mikaela, Yuuichirou is his reason for life. He’s his everything".
 * In Sakura-Con 2016, there was a panel organized by Funimation and the official WIT studio staff that was working on the anime. In one of the answers, one of the WIT studio staff, Koizuka (who has worked as an assistant directer for both seasons in the anime as well as episode directer and storyboard for the second opening), answered, "Both Shinoa and Mikaela like Yuu. We really enjoyed that triangle when creating this anime".
 * There, another WIT studio staff (Yamada, who worked on the character design and was the chief animation directer for the first season) was asked who they liked better with Yuu, Mika or Shinoa. They answered, "Mika. Mikaela".
 * In an extra chapter (titled "The Demon Army of Ikebukuro), Yu was dreaming about Mika being killed by Ferid, and woke up from the nightmare in class while screaming Mika's name. Shinoa then asks him if he was dreaming of an old girlfriend. Yu responds with "What? Heck no! Mika isn't a girl", without denying the romantic connotation that Shinoa was implying with the comment.
 * Every night since the day he escaped from the vampires, Yu had nightmares of Mika getting killled by Ferid. Yu even says in the aforementioned extra chapter, "Every time I close my eyes, I have the same dream. No matter how many vampires I kill, I still see the same dream over and over again. A dream where I watch my best friend, Mika, get killed..."
 * It is interesting how he called Mika his best friend, instead of the often used term "family". It is also important to note how he only thought of Mika instead of thinking of the deaths of the others in the Hyakuya orphanage.
 * Some of the lines from the opening theme, which is Yu address to Mika, refer to the events of the manga after chapter 90: "We will overcome. Your salvation has begun", "You make me realize who I need", "I'll be there hold on, They'll change you somehow. So where are you now? I'll reach you by dawn, before you can be turned, Illusions are torn." "If you wanna fight with me, Then go ahead fight with me".  Also, some lines from the ending theme, which is Mika address to Yu, refer to the same events in the manga: "I must be sacrificed, So can I help you all? I'll be a scapegoat if I can. My resolution failed and all who died... Light of day still hurts me." "You're waiting right here. A way for me to make it back, some way I won't need to attack. Everything has gone so wrong" "Come on break it down for me! A river will flow. You are not my enemy!" "Are you still my family?"
 * The ending theme also mentions the words of love twice: "I need your blood, You read love reciting" "Calling, screaming inside of my soul, It’s my fear of loving what’s dearest to us all."
 * When volume 26 was released, the manga was pictured alongside another manga called "Twin star exorcists". While the side of the Seraph featured Yuu and Mika, the side of the second manga featured Benio and Rokuro, the main characters. The caption between it read "Two titles led by strong unwavering love" which clearly compares Mika and Yuu to Benio and Rokuro. Benio and Rokuro are the canon married couple who love each other very much. Thus, the magazine compared Mika and Yuu's love to Benio and Rokuro's. Another inscription read "Yuuichirou and Mikaela, together in the ending world".

Variations

 * MikaYuuNoa refers to the ship between the two and Shinoa Hiiragi.
 * Yuichiro Harem refers to the ship between the two, Shinoa Hiiragi and Mitsuba Sangu.