Yuuki Tenpouin

 "An Eye for an Eye, a Tooth for a Tooth, and the Requiem of Fury for Evil - Yuuki's Addition to the Code of Hammurabi

Yuuki Tenpouin is a Code:Breaker whose codename is Code: 03. He has the ability to manipulate sound.

Basic Information
He speaks using Kansai-ben. He sleeps in a mansion and is referred to as President by the servants. He is actually very intelligent, graduating at the age of 12, but only because he hated studying. He runs a successful corporation that focuses around his childish ideas (later based on his friends) to create cartoon characters. However, all the ones he has made, he believes they aren't nearly as good as Nyanmaru. He is currently staying at the Student Council President's house after his house was completely destroyed. His sin is wrath. Yuuki is a free spirit whom nobody can ever control.

Appearance
Yuuki has dark red hair. His hair is wild, going spikey in the back but splits to two sides to cover his ears. He usually wears a long-sleeve white jacket hoodie with black combat boots. Most of the time, Yuuki wears plain grey pants with a loosley tied belt. When not in battle, Yuuki wears a black shirt with tan pants. He has a barcode on his chest, revealing his origin as a specimen of a barcode project of Eden where they tried to create genious youths with incredible abilities.

When angered, his skin turns red, indicating he is going to create a sound guard, Scarlet Phoneme, around himself.

His Lost Form is a red cat with simple, black eyes but he keeps his necklace on. He is 165 cm tall.

Yuuki has long white hair with long fringes and a more muscular and adult-like body when the Voice of Life is invoked.

Personality
A major love of his is the stuffed animal named Nyanmaru. Despite his violent tendencies, he genuinely rewards kindness, and apologizes by giving gifts to people - particularly Nyanmaru merchandise. Yuuki has mistaken Sakura as the true identity of Nyanmaru when her saying reminds him of the animated character, as such he calls her Nyanmaru instead of her name hence.

At first glance, he seems pretty calm and childish but goes on a rampage if anyone insults or soils Nyanmaru; Ogami Rei describes him as the "most barbaric Code Breaker": "He'll attack both friends and enemy alike... in other words, Yuuki is the most barbaric Code: Breaker." When he turns into his Lost Form, a small red cat, he still retains his rage and his ability to speak, even going so far to attack anyone who makes fun of him in that form. He is also known to be very bad mouthed in his Lost Form. This form could be one reason why he is so fond of the anime character Nyanmaru; another could be because Nyanmaru seems to be friends with everyone.

It has been said that the way Yuuki acts isn't his "True Self." It might be that Voice of Life is Yuuki's true self as it is a peculiar gene of a special character embedded into him. Rui Hachiouji also thinks Voice of Life is "a supreme being" and like "a deity". But, if the "True Self" has something to do with personality, then it could be the fact that Yuuki has become fond of others than Makoto and Shigure during the series.

Like Heike Masaomi, he too seems to not prefer the idea of killing, as he went out of his way to save a pregnant woman and a small child from an explosion. Nevertheless, he hates Heike and unlike the others, he doesn't fear him, going so far as to pour tea on his head. Still, he comes to help Heike when the young man is in battle against Saechika Hachiouji, stating Heike is the only one he accepts as the second among Code: Breakers.

He seems to have suffered a traumatic past, resulting in him becoming kind rather than evil. Yuuki usually protects others from danger, no matter what, and tries to help them in any way he can (though his ways are usually a little odd).

He hates Eden, but has joined the organization so that he can take it down. That hate is also the reason why Yuuki has to stay in touch with Eden.

Background
In chapter 94, we learned that Yuuki, Makoto and Shigure used to be best friends and played together. However, due to an accident, Makoto was put into intensive care.

In chapter 99, other children avoided Yuuki's uncontrollable sound waves and called him "evil" and a "deadly weapon". When children escaped from the boy, they stomped on some tulips. He mounted a plaque for the purpose others would not do so again; that was when Makoto met him for the very first time. Makoto told Yuuki he was so kind, strong and amazing while he worried about flowers like that. Yuuki was surprised there was someone who was not scared of him, but Makoto just said there was no reason to be since Yuuki was an "amazing guy". Makoto called Yuuki "Yu" and said he was happy to be Yuuki's friend.

In chapter 104, Makoto ran to Yuuki and appeared shocked when he understood Yuuki had jumped off the cliff just because of a dog; Yuuki simply answered the dog had been in "serious danger". Shigure hit Yuuki and the boy angrily demanded to know why it was wrong to want to save a dog. Shigure just answered by saying that if Yuuki did not know that, he should not talk to him. Makoto explained Yuuki that Shigure was just worried about him because he was Shigure's precious friend; Makoto also added he felt the same way about Yuuki.

In chapter 105, a flashback of Yuuki showed that he was about to help some injured people in an accident. Yuuki was persistent on saving those people despite resistance from Shigure and Makoto. He used his sound powers to help people. However, a huge chunk of debris almost crushed him, only to be saved by Makoto. This caused Yuuki to stop making friends and spending his time with his powers to save Makoto, saying that is his resolve for being a Code:Breaker. Yuuki (in Lost Form) and some other cats were protected by Ogami in an explosion. It was the first time they met; Ogami had taken down a bad person who still had power to fight back and he made that explosion. Yuuki and other cats had come so near to see that bad guy that they would have been in big trouble without Ogami shielding them. Yuuki told Ogami he was the third Code: Breaker and he had wanted to see how the newbie was doing. Ogami threw the cat down from his shoulder and said Yuuki should not get intimidate with him and that one should pursuit one's goal alone. Yuuki told he liked Ogami's resolve and added: "... Hey, sixth. It's not like I'm gonna be friends with you, but... I seriously am taking a liking to you."

History
When he was first introduced in chapter 35, he hadn't eaten in three days, forgot where he lived, lost his wallet and gave his phone to a stranger (just because that old man said he wanted it) and spent the rest of his money on a crane game. He said a man who tried to make him take many Nyanmaru-toys with him that a blue-coloured flame could be a good choice if one should be burned since blue fames are the most beautiful; he clearly showed how much he appreciated Ogami.

Sakura Sakurakouji noticed him the first time when he had fallen on the shop floor with many Nyanmaru-toys in the same chapter and she became worried because of him. Yuuki asked Ogami to treat him something since he was hungry and they got an opportunity to speak for a while during his meal. The boy said he did not want to work but sleep over Ogami's house and Ogami said Yuuki could do whatever he wanted to do. Yuuki also said he had a souvenir Ogami wanted the most with him before falling asleep with his eyes open while standing. However, he woke up very soon and tried to give Sakura a Nyanmaru doll for her genuine concern for his well-being, A man with his friends shoved Yuuki down before the boy could give a toy to her. When Yuuki noticed stained Nyanmaru on the ground (because of the man's spilled coffee), he punched the man down and threatened to kill all of them one by one with teeth bared and a crazy look in his eyes. He even fisted Toki Fujiwara, who was in his Lost Form and was an ally.

In Chapter 36, he gave all his Nyanmaru to Sakura before starting eating again. There were many Nyanmaru-posters on the walls in that place. He revealed he was eating so much to earn coupons to get Nyanmaru-merchandise. The boy attempted to get a golden Nyanmaru toy for Toki as compensation for beating him up, even though the latter didn't want it. Yuuki ran after a running Nyanmaru-toy when Toki made it moving, trying to get Yuuki out of his sight forever. He got so mad when a little child got a golden Nyanmaru which was the last one in the shop that Sakura and Toki had to hold him back; otherwise he would have attacked the little girl who "was planning to doom his life". The boy apologised for not getting the golden Nyanmaru and tried to give Puppy to Toki instead. Yuuki asked Ogami how much longer he was going to wear something (a ring) on his finger and said after that: "Ah, that's right. 'That guy'... gave that to you, right?" After that, he remembered his souvenir and told Ogami that the one Ogami was looking for was returning. The boy also told there were many dangerous people in the country once again because of the person Ogami was searching for and suspected that: "...This place will once again become hell. Many people will die.. Just like before..." In chapter 94, Yuuki was trying to find Ogami with his Sound powers, but he could not. Shigure said his power sure was useless, but Toki defended Yuuki a bit by saying it was not so easy to find Ogami after they had lost him. Shigure reminded Yuuki that his foolish sympathy only killed people, "as with Makoto". The boy tried to explain Makoto was still alive, but Shigure told Makoto was already dead and it was Yuuki who took him away. Yuuki ran away after that; Shigure called him "a wimp" but Toki said he was not going to betray them since he hated Eden, but had never once left work undone. Yuuki went to the hospital to see Makoto and told he should not worry about a thing because he would be fine under Eden's care. The boy revealed also that Eden's medical care is 50 years ahead of anything else so they would certainly make Makoto feel better. He said he was on a hunt after "Blue Flame" and he would take down the bad guy so that Makoto would get a right to test a new medication before anyone else. Yuuki was smiling while telling about going after Ogami, but he still seemed unsure, probably because he did not really want to hurt the person whom he admired. The boy looked a little bit happier when he told Makoto that Shigure was waiting for him to awake, too, so that the three could play together again.

Chapter 98 started with a memory of Makoto giving Yuuki a device (a keyer/a paddle) which Yuuki could use Morse codes with. Unconscious Makoto was then shown and he held that same device in his hands while Yuuki told Makoto to wait while he would hunt down the Emperor. Toki said that Yuuki should just leave Ogami for him since the boy could not possibly hunt down his "beloved sixth". However, Yuuki just glanced him coldly and Toki got a little horrified because of his blank expression. Yuuki just touched his necklace and left, ignoring Toki's question of what exactly happened between him and Makoto. Then, he went to the school where Ogami and Sakura were and shattered the windows with his Sound. The boy approached Ogami when Sakura stepped between them and told Yuuki that if he was going to kill Ogami, he should get past her first. Yuuki just kicked her hard so that she was thrown on the ground, scowled at Ogami and commanded him to give up his arm already. Sakura still had some power to hang on Yuuki's leg and beg him stop; after that she screamed she would not let that battle happen. She also questioned the boy's reason to fight; he answered he had someone he had to save and he would not care about any lives or sacrifices, with a mad look in his eyes. Ogami had enough of Yuuki's reasoning and punched him, telling him that he, too, had become trash and got ready to burn him down.

In chapter 99, Yuuki attacked Ogami with Sonic Sew after avoiding his first attack. Next, the boy used Noise Crush on the ground which crumbled beneath Ogami's feet. When he was explaining Sakura how the invisible voice could not be evaded, Ogami said his favourite line when he kills: "Burn to ashes." and burned Yuuki who did not happen to get any serious damage. Ogami told him he was horrible when using another person as a reason to hurt others, but Yuuki said Ogami would not understand because he could kill his own brother like it was nothing. The boy also mentioned he could hear Makoto's weakening heart beat which said it wanted to live; he also said he could not bear with the sound getting weaker every day. Yuuki shouted he would do anything to protect Makoto's life and attacked Ogami. Just then, Ogami and Sakura's classmates wandered outside, trying to warn Ogami of thick fog. They barely avoided Yuuki's sound waves and saw the furious boy hovering over them (they fell down because of the attack). Ogami tried to fix the situation by lying about some movie making project, but Yuuki attacked him while he had undone his flame because of his classmates. A boy named Maeshun (Maeda) hit Yuuki so that he would stop hurting Ogami. The boy got pretty angry after that and hurt people around the area with his sound waves so that they got some wounds. Youngsters called him "monster" and that made Yuuki remember his past. Yuuki explained he had always been called like that, but Makoto was different; he was like an "angel". However, the boy still felt painful because of Makoto's bad state because of him and that made him attack fiercely again. He told Ogami to give his arm to him again but, then, Ogami's classmates shielded Ogami from him and shouted they would never move away. They were trying to make Yuuki see they and Ogami were friends because Ogami would always help them if they were in trouble; Yuuki did not care but attacked. Ogami protected all of them with his flame and told Yuuki he would never let him hurt them.

In chapter 100, Yuuki was along with the other members of the Code:Breakers and Sakura, going to the beach in summer. Suddenly, when they had arrived there, he lost his powers among others. He climbed on Toki's head, trying to avoid getting wet in his cat form. A big tide crashed into them and Rui saved them from drowning. The boy got hit along others when he stared Rui's wet body for too long. The next day, Yuuki got sunburns like all the others.

In chapter 101, Yuuki asked if Ogami's friends meant anything to him since he had not told about his powers to them. Ogami told they were complete strangers to him and attacked while shouting Yuuki should not do anything to them. However, Yuuki used his Scarlet Phoneme in order to protect himself from Ogami's attacks and to gain a greater power. He explained how his technique worked and told Ogami should give his arm to him. Youngsters asked who they were and the boy answered by saying they were Code: Breakers "who judge evil that the law can't". When Yuuki attacked with sound waves later, they hurt Ogami's classmates even though people were farther from him than before. Kouji explained that barely nothing was safe from Sound and that if it lasted for too long, it could be life-threatening. Yuuki told Ogami he understood how much Ogami wanted to save the "strangers". He said that ever since he met Ogami, his heart was shaken over and over by him. He also admitted that Ogami is an idiot that he seriously loves. However, he was still determined to save Makoto and lunged against Ogami, demanding his arm. Ogami asked if they should go to hell together while attacking with his flame but Yuuki managed to rip his arm off.

In chapter 102, Yuuki wondered if Ogami's arm would be enough to save Makoto. Ogami died after that. Yuuki still thought things for a moment before reaching out for that arm. He happened to be too late, then; Sakura snatched the arm and screamed she would definitely save Ogami. Yuuki did not give up but attacked her as furiously as before with his sound waves. He saw his attack was for nothing and mocked Sakura a little bit because she is a Rare Kind person. Sakura questioned him since she was sure Ogami was the person Yuuki liked the most. The boy became angry and said Sakura did not know anything of the real him; they had just "played house" under the same room. Yuuki went so far that he said Sakura was disgusting and that she really knew nothing of the loneliness Code: Breakers had to endure. Just when he was trying to attack the girl, other students came between them. They told Sakura to hurry and retrieve Ogami's arm. Yuuki was astonished and asked why they did come back; he became enraged because the youngsters did not honour Ogami's feelings and still claimed to be his friends. Students were trying to hold him off and explain they just did not want Ogami end up dead, but the boy still managed to punch a guy named Dekasugi hard. Yuuki lost it and screamed how his feelings towards Ogami were a whole lot stronger than theirs; at the same time, he remembered times with Okami and Makoto, too. He made a fierce attempt to get that arm when it suddenly released huge flames towards him.

In chapter 103, Yuuki said that Ogami wanted to protect the students so badly that his soul did the work even if his body was dead. The boy attacked Ogami with Noise Crush when the latter had come alive again. Nevertheless, Ogami burned his sound and he said that pitch black flame was interesting.

In chapter 104, Yuuki told Ogami he was a fool since the boy was not going to be stopped by the black flame. He mocked Ogami who was "playing friends" with his classmates and told him that helping the students was hilarious, then attacked. Ogami managed to burn the boy's sound waves, but Yuuki attacked from above with a very wide attack. Ogami saved his classmates by burning them so that only Yuuki's Sound disappeared; Yuuki appeared astonished. Then, the two clashed on each other and Yuuki shouted Ogami was "10 years too early" to win him. The reaper of the flame came out, however, and burned his Scarlet Phoneme away with Ogami saying: "Yuuki, now, burn to ashes... along with your fallen soul!" Ogami had enough of kindness to stop his attack by snapping his fingers before Yuuki completely lost his power. The boy lost it and screamed that Ogami should give his arm to him since he already had had it. Then, Yuuki told Makoto was waiting for him and tried to punch Ogami, demanding him to die, but Ogami told him angrily that Yuuki would be a murderer if he died so he would never die. Ogami also explained he would not let Yuuki to become like Hitomi and his brother, a murderer; it was more fitting for Yuuki to "loaf around and wanting to become like 'Nyanmaru'". The boy remembered his past with Makoto and Shigure after that. Yuuki understood Ogami had done everything for him and (probably) spluttered that if he had met Ogami in a normal world without any Code: Breaker-stuff, they could have become friends. It was revealed that Yuuki's necklace actually contained pills, confirming what Toki said in chapter 98 that it was a risk when Yuuki started to struggle in pain after he ate it, even worrying Puppy.

In chapter 105, Ogami and Sakura were worried about wriggling and drooling Yuuki. The boy just grinned and said everything was just merely starting. Then he released an enormous sound wave and told that the medicine he ate forcefully amplied his powers and he couldn't lose his powers. Ogami answered by saying that he really would not have another choice, then, and the two started their fight again. Yuuki was thinking during the battle that the Code: Breakers were nonexistent and they had no names, proofs of their existence or even any leftover memories. Ogami mocked him by saying he had not improved at all and the boy just said Ogami could not beat Code: Names with the kind of power he had at the time. Yuuki tried to give all of his powers to Ogami using Sound Life, saying Ogami was the only one able to help save Makoto and everyone else while Yuuki was not able to hurt Ogami or anyone else anymore. During this process, Yuuki released a huge sound wave, alerting Toki, Heike, Shigure and even Makoto. When Yuuki fell, he started remembering fireworks. He remembered being suspicious about if the "game" was going to last when the fireworks shot up in the darkness inside of him. The boy also remembered, however, how "bright", "enjoyable", "passionate" and "transient" the fireworks were, remembering the times with other Code: Breakers and Sakura. Yuuki understood that the fireworks bloomed for a second before fading away, meaning how fragile relationships with other people really were. No matter how much the boy wanted to seclude himself from others, he still wished those fireworks kept blooming a little longer, meaning he had learned to appreciate others. Yuuki thought he was sorry because he could not bring down Ogami or save Makoto but he smiled anyway because he knew Ogami would be able to protect everyone instead of him. He almost killed himself, only to be stopped by Sakura's hug (her Rare Kind powers). The girl demanded to know why the boy was trying to kill himself. Yuuki said he was worthless and could not protect every precious person only by himself. Sakura said, almost angrily, that friends were for that reason and Yuuki should have told them about his situation since she and Ogami were ready to be his friends. The boy was shocked when Sakura hugged him and cried how humans were weak, had they special powers or not: "The hands of one person can take up no more than another person... That's why we treasure our friends who can help us... Protect everyone." Nevertheless, Yuuki pushed her away and told that was not acceptable because Makoto was suffering all alone, still. At the end, Yuuki heard Morse Code from Makoto himself, telling him that he realised Yuuki is really a kind-hearted person and hoped Yuuki would bring more friends to visit him (Makoto) next time: "I love how kind-hearted you are, more so than anyone else. Come visit me with more friends next time, ok?" Yuuki probably started to cry after hearing this with Sakura and Ogami smiling. Makoto continued: "You're my proud friend. Stay with me. Forever and ever, alright?" In chapter 106, Ogami's classmates got scared when Yuuki stood up bloody and panting. The boy bowed deeply and said he was sorry he had tried to hurt the students. The pupils were not ready to forgive him immediately but questioned Yuuki about what he had done to them. The boy just told them with a sad look on his face he could do nothing but to apologize since his sin could never be erased. Sakura got worried and not without a reason; Yuuki said to Ogami that he would accept his punishment from the older boy. Ogami replied by saying he would not let anyone else pass judgement on Yuuki and asked if the boy was ready to be burned by his flame. Sakura was going to come to help but Yuuki said sternly that he was a man, too, and would take clear responsibility from his actions. Even Puppy looked sad when Ogami released his flame towards Yuuki. Sakura thought back what had happened and realised everything was wrong; she ran to stop Ogami once more but Maeda punched Yuuki down before Ogami could kill the boy. Yuuki wondered why Maeda did what he did and the student could not give a clear answer. He shouted, however, that he would have nightmares if Yuuki just died without telling them (the students) anything and that he would never forgive Yuuki for trying to kill Ogami and hurting Sakura. Nevertheless, he also yelled that nobody had the right to take Yuuki's life. Other students became more peaceful after hearing Maeda out and they asked the reason behind Yuuki's actions, begged him to promise not to do those things again and told they would only let that kind of thing pass once. A couple of students started to argue about man's honour, Aoba Takatsu remembered Sakura's words: "If justice means to blindly refuse evil deeds, then I don't need it!" and said she was starting to understand those words.

Yuuki started to think all of them as Nyanmaru because he thought they were as friendly as Nyanmaru were. Still, the boy raised his hands towards the sky and said his sin would remain because he had hurt others with them. Ogami remembered how Yuuki had saved him twice with those sinful hands and reminded the boy about those times. He also said that Yuuki's hands might had blood on them but they were still Yuuki's. Then, Ogami explained Yuuki would not have to "try to gain forgiveness" or repent the sin he had committed; the really important thing was that Yuuki should live with his burden and do it only for himself, not for Makoto. The boy was astonished after Ogami's words and told Ogami was weird in a way he did not know. He also added he had always liked Ogami but liked him much more now. Surprisingly, Yuuki got an idea about a new character and scribbled it down on the wall. That character was based on Ogami and when the sixth started to beg Yuuki not make picture books about him, the third told Ogami everyone knew who he was now, anyway. Ogami asked Yuuki what the boy was going to do about witnesses but Yuuki just answered he would keep his mouth shut so nobody at Eden would know. After that, some blood spurted out of Yuuki's body and Ogami said the boy would need some rest since he had lost most of his power. Yuuki, lying on the ground, said he could not rest because he would have to get his powers back and go see Makoto. Ogami doubted if Yuuki could return to Eden that easily. Yuuki remembered Makoto saying he would like to see Yuuki's friends so Yuuki asked if Sakura and Ogami would come to see Makoto with him; Ogami agreed. When Ogami's flame came out on its own, Yuuki wondered what was the voice that could be heard inside of the flame.

In chapter 107, Yuuki asked Ogami if the older boy was going to look for "that big one" and Ogami replied positively. Code: Emperor tried to attack Ogami but Yuuki's Sound protected him by covering him with the Scarlet Phoneme. Yuuki explained that happened because he put his sound into Ogami; the boy also added the Sound seemed to like Ogami and hate Emperor. Emperor smiled haughtily and said the special power did not know its place. After that, Emperor took the Sound from Ogami as a payment for Belphegor, the power turning into a brooch in a process. Sakura was hurrying to look for Uesugi Hajime but Yuuki stopped her by grabbing her hand and explaining that Uesugi was not injured or anything but a power user. Ogami seemed not to like the way the boy revealed the thing but Yuuki just said Ogami would not be able to protect his school mates if he kept quiet about the fact. Suddenly, an earthquake started and Yuuki warned the others that the old school building would collapse. Re-Codes came to save the day after that.

In chapter 108, Yuuki got badly injured by Heike's attack, when he protected Sakura's classmates from the attacks.

In Chapter 113, he was training with the President.

In 118, Yuuki appeared in front of Toki to protect Ogami; he told Toki to stop and that he would not let the Joker to take Ogami's arm.

In chapter 119, Toki asked Yuuki what the boy had done recently and Yuuki answered by saying he had been training with President so that he could protect the others. The young man seemed to think Yuuki was on the same side of Ogami because of pride. However, the boy said he did not care about his side and that all the other members of their group were precious to him. He tried to convince Toki not to go after Ogami so keenly that he even tried to give him a golden Nyanmaru. Toki was truly astonished and asked what kind of training Yuuki had been doing since the golden Nyanmaru was so rare (implying there would normally had been no way for Yuuki to give up one). Yuuki replied he did not want the Nyanmaru he did not get himself. The Joker said it was just like Yuuki to go and get a Nyanmaru for him and said he was sorry he could not take it; then, he said he needed to hunt down Ogami's arm. When Toki was already leaving, Yuuki asked if the young man had opened Pandora's Box because of his loss against Ogami and Kouji. The boy also wondered where hard-working Toki was and told Toki he was pathetic. Toki got furious and told Yuuki to try and stop him by force.

In Chapter 148, Yuuki triumph over his trial of the Kibou Festival, however, did not gain any new strengths nor gain any of his original power he gave to Ogami.

In Chapter 159, while protecting the crossmarks, Yuuki gains a new ability making him more powerful and changing his apperance of him looking alot older. It is hinted by Utah that Yuuki might be the "Forbidden Fruit Apple of Eden". It is unknown at this time what part Yuuki plays as the apple.

Sound
High Intellect: Despite his rather odd and unusual behavior, Yuuki has been known to be extremely intelligent. He graduated from the famous Cambridge University at only 12 years old, which literally is amazing as there are no known people (even among high status) that are are able to graduate at such a young age. It was revealed in chapter 148 that Eden made Yuuki by using the genes of intelligent people and power users. When he was younger, he was already doing highschool level studying.

Skilled Hand-to-Hand Combatant: Yuuki has been shown to have great skills in melee combat as he was able to smash two thugs simply by knocking both of them out and even beat Toki till he flew in mid-air.

Techniques
Speed of Sound: Yuuki's primary ability is his immense speed which has been acknowledged by many to be his most important skill. He has been able to avoid almost any attack thanks to this ability. It can be also used offensively as he can sneak attack his opponents before they can even react.

Sonic Sew: Yuuki forms soundwaves around his hand and uses their high frequency to pierce his opponents.

Noise Crush: Yuuki places his hand to the ground and causes vibrations to form, and then destroy the ground apart.

Scarlet Phoneme: It is a stronger form that Yuuki develops by creating high density frequency around his entire body; his skin turns scarlet red, pupils turn black, irises turn yellow and his hair turns white. He is able to emit sound around over his body automatically without him being the one emitting it. The sound waves are so dense that they vibrate through the ground to the point where he is able to cause great damage to Kibou High school (despite the fact that the school was covered a great deal with Shibuya's blood). He appears to have increased both his offensive and defensive capabilities as he explained to Ogami: "I use very dense and high frequency sound waves to shelter my body, revitalizing it to its max. Since I'm inside this shell, even if you want to burn me, your blue flame will never reach. In other words, nothing's going to work on me, nor can anything stop me now. I can't hold back anymore, either." However in chapter 104, Ogami managed to burn off his Scarlet Phoneme with his Belphegor.

Sound Life: Yuuki gives his powers to someone else. It seems to make him bleed and gradually lose his life if he is not stopped before finishing.

Echo: In chapter 124, Yuuki used this technique to stop Toki from going after Ogami's arm. Toki explains that it: "You used 'Echo' didn't you? In this underground tunnel, it's easy to create an echo using a single sound. The echo multiplies and bounces back to you, As you absorb them to multiply your power. How your drawings sing along is due to echos coming from several directions...like on the mountains." While this echo makes Yuuki faster and gives him a boost in power, the effects it has on his body are dangerous.

Makoto
Yuuki's friend who made a form of morse code for him.

Shigure
They were once friends in the past, they lived in the same facility.

Rei Ogami
Yuuki greatly admires Ogami, finding him very kind.

Trivia

 * His lost form is, similar to Kouji, an animal type. Interestingly, they both also have similar numbers in their group.
 * He can sleep with his eyes open.
 * His body made a Metamorphosis when he used his second special power.
 * He has a scent of warm milk, mentioned by Sakura in chapter 52.
 * He refers to his friends with numbers.