|“||Surpass your limits. Right here. Right now.||”|
Yami is a tall man with a muscular build. He has black eyes and black hair of medium length that is messily combed backward. Additionally, he also sports a stubble mustache and beard.
Yami's attire is very simple and consists only of a white A-shirt and black trousers. The trousers have an extra layer of tan leather that covers his outer thighs and down to his knees. The trousers are only supported by a belt around his waist. Yami wears another pair of belts, one of which he uses to carry his grimoire. Lastly, he wears black high boots that cover most of his calves.
As the captain of the Black Bull squad, Yami wears a black banner with the squad's insignia on it. He wears it over his right shoulder and it is attached by two strings to his left shoulder. The banner also has tattered edges, seeming to have been ripped off from a bigger banner.
For the Star Awards Festival, Yami wears a simple robe over a fundoshi, and a twisted hachimaki tied in the front. He also carries an uchiwa. The fan and the back of the robe bear the kanji 祭 ("festival"), and the left lining of his robe has 暴れ牛 ("rampaging bull").
Yami is normally a very quiet person that only speaks a few words. However, he is also a hot head, who could be easily enraged by something as small as being bumped by another person. Yami also has a penchant for intimidation whether he uses threatening words or physically hurts his target. He also tends to immediately go straight for a more physical solution to any problems or confrontations, such as when he destroys a part of the squad's headquarters to calm his subordinates.
Furthermore, he also prefers instilling tough loves to his subordinates by giving them dangerous missions. He believes that it is the best way for them to overcome their limits and grow stronger. Yami also does not discriminate people according to their social status or circumstances where he is willing to accept Luck Voltia, Noelle Silva, and Asta to join his ranks, even though he is aware of each of their problems.
He was born in the Land of the Rising Sun to a pair of fisherman. As a young man, he goes fishing, shipwrecks, and washes ashore in a strange country. There he is met with troubles because of culture shock and racial discrepancies. When Yami receives his grimoire and releases his Dark Magic, others hate and fear him, except for Captain Julius Nova Chrono, who is fascinated and invites the boy to join the Magic Knights.
The day after his nineteenth birthday, Yami is enjoying noodle soup when the Thorn Magic curse on House Roselei causes the soup to spill on him. Cutting through the thorns, Yami confronts and chastises Charlotte Roselei for relying only on herself. At that point the curse is broken and dissolves because Charlotte falls in love with Yami.
Before the Magic Knights Entrance Exam, Asta runs into Yami and other members of the Black Bull squad. Yami threatens to kill the boy but is stopped by the beginning of the exam. During the exam, Asta's athletic ability and determination impress and weird out the Black Bulls captain. When none of the other captains recruit Asta, Yami releases his Magic Power and tries to intimidate the boy. However, Asta remains determined, and amused by the boy's response, the captain recruits him. Yami also recruits Noelle Silva.
Later, Asta returns from the bathroom, and Yami threatens Asta again for making him wait and then throws the boy through Finral Roulacase's portal to the Black Bulls' base. There, Yami welcomes Asta to the squad.
As members are casing a ruckus, Yami yells at them to cut it out, slamming his fist against the wall. They stop and greet him on his return. Yami then introduces Asta to the squad, while also telling Asta that some of the squad members are absent. After Asta introduces himself, Yami watches with the rest of the squad as Asta takes on Magna Swing's Black Bull Initiation Ceremony. During the ceremony, Yami notices that Asta's Demon-Dweller Sword can cut and reflect mana. After the ceremony Yami watches as Asta receives his robe.
Later that night, Yami notices that Noelle's magic has started to rampage. Upon reaching Noelle's location, Yami comments about how they will need Asta to cut the mana since everyone else could hurt her. As Asta is hit by the rampaging Noelle, Yami catches Asta and then throws him while telling him to cut through the mana. After Asta manages to save Noelle, Yami compliments the kids for doing a good job.
The next day, Yami gives Asta and Noelle their first mission: to accompany Magna on a boar hunt in Sosshi. Yami explains that the mission comes from a lost bet, and when Asta and Noelle complain, Yami forces them to take it by threatening to kill them. After Asta, Noelle, and Magna return from their mission, Yami compliments them for doing a good job and reveals that they have obtained a star. After Yami reveals that the squad has negative thirty stars, Yami gives Asta and Noelle their monthly wages.
Later Yami sends Asta on a mission from the Magic Emperor to explore a dungeon, with Noelle and Luck Voltia. After the three left for the dungeon, Yami talks with Vanessa about sending Asta and Noelle to the dungeon and the reason he sent Luck with them. After a while Yami remembers that the Golden Dawn sent a group to the dungeon too, and wonders if they will get along.
A week later, Yami notices that Asta is up and tells him that he did a good job with the dungeon even through he was in tatters. Yami also tells Asta that he is to head over to the Magic Knights headquarters and report what happened in the dungeon. As Luck gets excited to head to the headquarters, Yami informs him that he will be going on a mission with Magna instead. Charmy Pappitson offers to go in Luck's place, but Yami says that she is not going since she will just eat while there.
After Asta, Noelle, and Charmy return from the capital and reveal that they have been promoted for their parts in The Undead Invasion, Yami explains the ranking for the Magic Knights and how Magna and Luck have not ranked up since they joined. Yami also tells Asta that he has done a good job, and noticing that Asta is worried, tells him that Fuegoreon Vermilion will not die. When Asta decides to train, Yami tells him that he should relax. Suddenly Finral invites Asta out, and Yami points out that Finral needs to work.
After Noelle reports about the kidnapped children, Yami has Finral take them both to Nairn. Upon appearing in the cave, Yami blocks an attack by Licht. As Finral uses his magic to get the children and wounded to safety, Yami tells Finral to come back while blocking the spells that Licht launch at Finral. As Asta is amazed by Yami's skill and sword, Yami explains what his katana is all the while continuing to counter Licht's spell. Licht tries to attack Yami from behind, but Yami easily counters. As Yami and Licht start to talk, Licht tells a story about a powerful group that was killed by humans which Yami counters by tells Licht how he became the captain of the Black Bulls. As Valtos yells at Yami for making fun of Licht, Yami just yells back about Valtos' face but is wounded for trying to counter Licht's spell.
Yami notices that Licht's attacks are gaining speed and continues to defend against Licht's attacks. Yami asks if Licht is the one that attacked Fuegoreon, which Licht affirms. Yami then launches a spell and manages to cut Licht on the cheek, and tells Licht that he will show him that true strength of a Magic Knight captain. Yami then tells Asta that he is going to do that same, which shocks Asta. Asta says that he cannot do what Yami is doing, but Yami says that Asta is going to copy his defensive style. While countering Licht's spells, Yami explains that he is using Ki to counter all of Licht's spells.
When Valtos attacks Asta, Yami easily defends Asta and then tells Asta to surpass his limits if he wants to be the Magic Emperor. As Asta tries to use Ki and fails, Yami kicks him and explains how to use Ki; however, when Asta manages to use Ki to reflect Valtos' Magic Bullet, Yami considers him a freak for learning so quickly.
Angered, Licht lashes out with his Bright Judgement Whip, which Yami defends against, but the spell causes the cave to collapse. Yami and Asta are buried but survive by using Ki and dodging the rocks, and Yami comments that Asta will be hitting Licht next. Yami then quickly takes that back and says that he still has to show Licht the true power of a Magic Knight captain, while Asta still has to face Valtos. Yami releases his mana and continues to battle against Licht. While battling Licht, Yami says that he wants to hear the rest of his story which Licht finishes his story and explains how flawed the Clover Kingdom is. As Licht says that they are going to fixed this kingdom, Yami replies that he cannot stand the kind of guy that Licht is and continues to battle against him.
As Valtos tries to help Licht, Yami easily defends against it and admonishes Asta for not having finished his fight with Valtos. As Asta manages to defeat Valtos with a simple punch, Yami laughs and compliments Asta for his win. Licht takes this opening to attack Yami, who easily counters Licht's spell and manages to wound Licht. Licht talks about Yami's Dark Magic and what it is capable of, which Yami confirms. Licht decides to use his greatest spell, and Yami wonders what to do against that powerful spell. Yami puts up a barrier around himself and Asta, and both wonder what to do once Licht launches his spell. As Licht launches the spell, suddenly Gauche Adlai arrives with Finral and reflects the spells with a large mirror.
After Licht is defeated, Yami compliments Gauche for defeating Licht but tries to take the credit for recruiting Gauche into the Black Bulls. As Yami prepares to restrain Licht for transport to headquarters, three individuals suddenly appear. When Liar suddenly appears in front of Yami and touches Yami's grimoire, Yami quickly attacks and manages to wound Liar's arm. After Licht introduces them as the Third Eye and boasts about their strength, Liar attacks Yami with Dark Cloaked Avidya Slash, and the captain counters and says to stop copying him. Vetto blitzes Yami and breaks his katana, to Yami's surprise and anger. Fana then blasts the Black Bulls with Salamander's Breath, and Yami defends his team and takes note of her elemental spirit.
As Yami continues to counter the three attacks, the others are worried about him but Yami tells them not to worry since he will surpass his limits. As the Third Eye prepare to finish the Black Bulls, the attacks are blocked by Jack the Ripper, Nozel Silva, and Charlotte. After having brief conversations with Jack, Charlotte, and Nozel, Yami watches as the three face off against Lair, Fana, and Vetto. When Finral mentions that he can create another portal, Yami gets excited and has Finral transport him. Yami appears above Licht and swings his sword, but Licht anticipated this and has his own spell ready. However, this is a ruse to cover Asta, who suddenly appears from the smoke and slams his Demon-Slayer Sword into Licht.
Yami compliments Asta for surpassing his limits and defeating Licht. Yami then watches as Licht starts to glow and release his mana. Yami and Asta prepare to attack Licht, but the Third Eye surround and seal Licht and his mana and retreat with Valtos. As he watches them disappear, Yami wonders if that means the Magic Knights won, and when Asta falls unconscious, Yami orders Finral to carry the boy.
Later Yami meets with the other captain, minus Fuegoreon and William, in a room within the Magic Knight headquarters. After talking with the other captains, William arrives, and as the others question if William is Licht in disguise, Yami says that William cannot be him since William does not use Light Magic. As Lil tries to lighten the mood by imitating Yami, Yami gets angry and yells at Lil while also saying that Julius better not have forgotten about them. Marx suddenly makes contact with them and informs them that they are to head to the dungeon, which Yami heads their with the rest.
Once there the captains listen as the prisoners, under Marx's control, reveal that Gueldre Poizot is the traitor within the Magic Knights. Gueldre claims that he is being framed, so Yami suggests that Gueldre have Marx look into his mind if he is not hiding anything. As Gueldre tries to escape, Yami and the others are blocked by Gueldre's Invisible Soldiers; however, Yami realizes that Gueldre's Permeation Magic cannot hide his Ki and Asta uses it to track Gueldre and hit him with the Demon-Slayer Sword. Lil then rushes to capture Gueldre before Yami and the other captains destroy the building. As the captains watch Marx displays Gueldre's memories, Yami comments that Gueldre might be better suited to lead the Black Bull squad because his illegal activities make him pitch black. Julius orders the captains to search their own squads for more traitors but not to make the information public.
After the captains are dismissed, Julius has Yami and Asta meet him, and they discuss the White Night Eye's search for magic stones, on of which is in the Seabed Temple. Julius gives the mission of securing the stone to the Black Bulls. Yami salutes and agrees to the mission. As they leave, Yami and Asta talk about how Yami let him join the Black Bulls because he thought he would achieve his dream.
While the Black Bulls party on Raque's beach, Yami searches for information on where to find the Seabed Temple and how to enter. He then returns to the beach and buries the squad in the sand before briefing them on the mission. Yami says that they will use Noelle's magic to get there, but when Noelle tries to back out since she cannot control her mana, Yami replies that she will have to surpass her limit by the full moon since there is no one else to take the mission.
A week later Yami watches as Noelle manages to gain some control of her mana and comments that they will be heading out. The Black Bulls gather in Noelle's Cradle of the Sea Dragon and head towards the Seabed Temple. After passing through the Grand Belt, they encounter a wall of magical whirlpools, so Yami grabs and throws Asta at it, ignoring that Asta cannot swim. Asta pierces the wall with Demon-Slayer Sword, allowing the the others to pass through. Yami offers Charmy a pastry for making a platform to lower them down, and as they enter the temple, they encounter several citizens. Yami intimidatingly asks to see the temple's boss, and in a similar manner, one of the men tells him that would be the High Priest, before several other citizens lead the Black Bulls. They enter the building at the top of the stairs, while the citizens wave goodbye as the doors shut.
Gifso greets them and tells that they will have to play a game to obtain the magic stone, to which Yami agrees. Gifso then announces the Temple Battle Royale, summons the other priests, and then separates everyone to different parts of the temple, with himself and Yami in a room to monitor the competition. Yami asks why he is not allowed to play too, and Gifso replies that Yami is too powerful. Pleased with the answer, Yami sits on the couch and watches the fights. Gifso asks what ranks the Black Bulls are, and Yami tells him that they are all low ranked Magic Knights, which makes Gifso laugh. As Luck, Magna, Asta, and Gauche knock out their opponents, Yami points out that their ranks do not reflect their strength.
Laughing, Yami suggests that they bet on which team will win, offering 100,000. When Finral tries to run away, Yami threatens to kill him if he does not fight, and Gifso summons a Monster Toy to chase Finral. Yami then sketches a more terrifying monster fish for the priest to summon. When Kahono puts Charmy to sleep, Yami declares that she will go without food for a week. He is then mildly surprised when Vanessa strings up her opponent, and is impressed when Asta replicates Kiato's movements and disarms the priest.
When the White Night Eye crash into the temple, Yami recognizes Vetto and decides to leave, but Gifso informs him that he cannot per the rules of the game. Yami tries to cut his way out but one of the White Night Eyes has trapped them inside. Yami then informs the Black Bulls about what is happening and tells them to surpass their limits, and Gifso announces a change in the rules.
Yami commends Magna and Luck even though their combined spell did not injure Vetto, and wishes for Asta to learn from them. When Noelle releases her mana, Yami wonders if she has finally awoken. He is then surprised with the power behind Noelle's Roar of the Sea Dragon. Vetto releases his demonic mana and regrows his destroyed arm, which greatly troubles Yami, so the captain yells for Noelle to run. When Vetto fires a blast at Noelle, Yami is glad too see Asta defended her.
Yami breaks through the spatial barrier and knocks out the White Night Eye members. Yami then arrives as Vetto is preparing to blow everything away. Yami first compliments Asta, Noelle, Finral, and Vanessa for defeating Vetto, and then confronts Vetto himself. He slices through Vetto and the cloud of mana. As Vetto's corpse drops to the ground, Yami points out that he did not fall into despair. Asta, Noelle, Vanessa, and Finral all hug Yami but he threatens them away with his sword. Yami then looks over when he hears Gifso crying over Kahono and Kiato. The High Priest thanks the Black Bulls and offers them whatever they desire, and Yami asks only for the magic stone that Nero has found in the temple.
Later while the others are resting, Yami holds a small memorial for Vetto. He then notices Asta and asks what he is doing here, to which Asta replies that he found some flowers and puts them by Vetto. Yami and Asta then talk about Vetto and his despair, but Yami tells him not to think about too much and just to chase his own dream. He then pulls Asta's headband down over his eyes and leaves the blinded boy alone.
A day later, Yami leaves with the rest of the Black Bulls to their headquarters. After their return, Yami heads to the Magic Knights headquarters with Asta, Charmy, and Finral and the magic stone and prisoners. Once in the royal capital, Yami thanks Finral, letting him go elsewhere. In the meeting with Julius, Yami recounts the events of the mission and hands over the prisoners, corpse, and magic stone. Julius praises the Black Bulls and Yami, and the captain responds that he just wanted to prove Julius and himself right on their choices. When Asta asks for Julius' signature, Yami offers to write it between Asta's eyes. Julius then asks if Charmy is Yami's child, but Yami refuses.
Marx suddenly contacts the Magic Emperor and alerts them that the Diamond Kingdom has invaded Kiten. Marx also says that the Diamond Kingdom's army is lead by three of their Eight Shining Generals, on which Yami then has to inform the confused Asta. After watching the Golden Dawn arrive and battle the army, Julius brings up that idea of sending reinforcements, and Yami suggests ordering him to go. When Asta asks to go along, Yami refuses since Asta is injured, but Charmy offers to look after him. Yami agrees and they leave to find Finral.
They sneak up on Finral and scare away the women he was talking to, and Yami then forces him to take them to Kiten. Upon arrival, they notice the giant tree, which Yami as William's World Tree Magic. Yami then orders the others to help the citizens as he heads up the tree. As he reaches the top, Yami senses Lotus trying to ambush William and defends his fellow captain, driving off Lotus. Yami decides that he needs to have a chat with William.
Yami asks William to remove his mask, but William refuses and asks if Yami suspects that he is the leader of the White Night Eye. Yami notes that William and Licht have different magic but same build, voice, and Ki. Yami mentions their shared past, which convinces William to remove his mask, revealing his scarred face. Yami listens as William explains his scar and talks about his childhood along with his meeting with Julius. Yami believes that William is telling the truth and decides to trust him. They then receive word that Diamond Kingdom forces have been defeated.
Yami collects Asta and takes him to see Owen, before heading out to gamble. Afterwards Yami treats the Black Bulls to a feast, celebrating the squad reaching zero stars. After Asta leaves the party, Yami listens as Finral tells everyone that Asta's arms cannot be healed. Yami and the others spy on Asta and after seeing that Asta is perfectly fine, he starts to cheer up.
The next day Yami is sitting in the common room and reading a newspaper when Asta comes down. He professes not to know where the others are. After finding out that they are searching for cures, Yami comments about how much better off they would be if they put this much effort in their normal jobs.
After Asta, Noelle, Finral, and Vanessa return from the Witches' Forest, Yami greets them and is unimpressed by Asta's healed arms. Asta points out that they have another magic stone, so Yami sends him for more booze. Yami then welcomes Vanessa back.
Later Yami forces Asta to take some time off from missions because he works too much. After the others return unsuccessful, Yami tells Charmy that he will not be paying her for the time she spent away. Yami then tells Asta and Noelle about the Star Awards Festival, and changes outfit before they head out. Once they reach the festival, Yami tells them to have a blast and that the ranking announcement will happen at 8 pm.
Coming to see what the commotion was, Yami meets up with Asta and teases Charlotte about her dress. When Vanessa shows up and challenges Charlotte to a drinking contest, Yami watches along with the crowd. After witnessing that Charlotte cannot handle liquor, Yami grabs her drink and reminds her of what he told her once. As the crowd heads towards the stage of the ranking announcement, Yami comments about how they are late.
Yami is surprised when Black Bull places second, and changes into his normal outfit. When Julius asks for one of the Black Bulls to join them on stage, Yami puts the Black Bulls robe on Asta before throwing him up onto the stage.
After the ceremony, Yami boasts about his squad's position to the other captains, which angers Nozel and Jack. However, Lil sticks up for Yami, and Dorothy snores which Yami still does not understand. As Nozel and Jack leave, Mereoleona Vermilion arrives holding Yuno and Asta. Yami laughs at them until he, too, is grabbed by the Crimson Lion captain. After also grabbing Charlotte and Noelle, Mereoleona carries them to the Ultime-Volcano Mountain Trail to train with the Crimson Lion squad.
Yami then heads out first with Charlotte and uses his Dark Magic to cut through falling lava. He then realizes that he and the others are being used to motivate and model for Mereoleona's men. After reaching the top, Yami sits with Charlotte and witnesses Mereoleona evade and punch Asta in midair.
Yami joins the men on their side of the hot spring and suggests peeping on the women. The Crimson Lions refuse, but Yami says that it is something men have to do. When Yuno also refuses, Yami tries to coerce him but Asta tries to defend his friend. Leopold Vermilion realizes that Fuegoreon also likes baths, and Yami tells the Crimson Lions that they should not be like their former captain but should surpass him. Convinced, the Crimson Lions head toward the partition, and Yami invites Asta, who refuses vehemently, shocking everyone else.
- Dark Magic: Yami uses this form of magic to generate and manipulate darkness. He primarily uses this magic by channeling it into his sword. This magic also has the ability to draw in other forms of magic, namely Light Magic, absorbing it into the darkness.
- Reinforcement Magic: Yami uses this form of magic to enhance his physical abilities. It also allows him to make up for the slow speed of his Dark Magic.
- Master Swordsman: Yami has described himself as a magic swordsman. He is highly proficient in swordsmanship; he easily fights on par with Licht, the leader of White Night Eye, with nothing but swordplay in conjunction with his Dark Magic, destroying the surrounding environment.
- Enhanced Strength: Yami is extremely strong, as he easily throws Asta a considerable distance with just one hand. He also has incredible leg strength, shown when he jumps to the top of William Vangeance's Great Tree Misteltein.
- Immense Reflexes: Yami possesses excellent reflexes, blocking Licht's light blades with ease when his subordinates and others could not even react to their speed, and nonchalantly counters the latter without having to turn around.
- Immense Durability: Yami is an extremely durable fighter, being unfazed when hit by Licht's light blades, and emerges completely unscathed at his attempted cave in.
- Enhanced Speed: Yami is very fast, surprising someone as fast as Licht with his speed. When Lotus Whomalt attempts to launch a surprise attack on William Vangeance, despite having to climb a massive tree, he arrives just in time to intercept him.
- Ki: A principle originating from his homeland, this skill allows Yami to use a sixth sense to perceive and react to unseen attacks and persons.
- Immense Magic Power: As a captain of a Magic Knights squad, Yami possesses an immense amount of Magic Power, shown when the anti-birds flee as soon as they realize his presence. This is further proven when the slightest release intimidates multiple people. After Yami blocks and counters Licht, Valtos wonders if the captain could rival the Magic Emperor. Gifso, the High Priest of the Seabed Temple, acknowledges Yami as being too powerful for his game. After watching his squad fight at the brink of death, he surpasses his limits to escape the White Night Eye's dimensional trap, and becomes powerful enough to defeat Vetto. Julius Nova Chrono states that Yami has grown more powerful after he returns to the kingdom.
- Grimoire: Yami possesses a three-leaf clover grimoire that contains various darkness-based spells.
- Katana: Yami uses a katana in combat. It is from his homeland, the Land of the Rising Sun. It was broken by Vetto durning their first encounter, but replaced with a brand new one afterwards.
- Magic Knights Entrance Exam
- Noelle's Magical Rampage
- Rescue the Children Mission
- Captain's Meeting: Finding the Traitor
- Temple Battle Royale
- Invasion of Kiten
- Star Awards Festival
- The Hot Spring Training Camp
- "...In the end... the most important thing about a Magic Knight is... magical power." 「...なんや かんやで... 結局魔法騎士に 求めりれるのは 魔力だ "... Nanya kan'ya de... Kekkyoku Mahō Kishi ni motomeri reru no wa maryoku da"」
- "Surpass your limits. Right here. Right now." 「今 ここで 限界を 越える "Ima koko de genkai o koeru"」
- "Protect whatever is precious to you. One day it'll lead you to protect something else." 「テメーはテメーの護りてぇもん護ってりゃいいさ いつかそれが誰かの為になる "Temē wa temē no mamoritē mon mamotterya īsa Itsuka sore ga dareka no tame ni naru"」
- "This is the first time I've seen royalty that was labeled a failure... If you feel like fighting against it all, come with me." 「王族の落ちこぼれなんざ初めて見たわ ...戦う気があんなら
黒の暴牛来れば? "Ōzoku no ochikoborena n za hajimete mita wa ...Tatakau ki ga an'nara uchi kureba?"」
- "Mr. Destiny, huh? I hate that bastard's guts. Who would even pay attention to him? I'd tear him apart and do whatever I damn well please." 「あーいイいイ運命さんね オレそいつ嫌いなんだわ 誰が言う事きくか ブツ潰してでも 好きにさせてもらうぜ "Āiiii unmei-san ne Ore soitsu kirai nanda wa Dare ga iu koto kiku ka Butsu tsubushite demo Suki ni sa sete morau ze"」
- "I like strong women, ya know? But there's nothing wrong in relying on others sometimes, right? And there's plenty strong people you can trust... among us Magic Knights, don't you think?" 「強えー女は好きだぜ? だがたまには誰かに頼ってもいんじゃねーの? そんな頼れる強ぇーヤツらがいっぱいいんのが オレ達魔法騎士団だろ? "Tsuē on'na wa sukida ze? Daga tamani wa dareka ni tayotte mo inja nēno? Son'na tayoreru tsuē yatsu-ra ga ippai in no ga Ore-tachi mahō kishi-dan daro?"」
- Yami's favorite things are tobacco, coercion, and interesting people.
- Yami is the most muscular character.
- Yami ranked second in the first Popularity Poll.
- Yami means "dark, black" in Japanese, a reference to his magic type.