Killer B

is a shinobi from Kumogakure and the jinchūriki of Gyūki, the Eight-Tails.

Background
At a young age, B along with several other children were gathered in order to select a tag partner for A. Out of all the children gathered, B was the only person able to successfully perform the Double Lariat with A. As such he was given the name "B", and A stated they would be brothers from that day on. Since the age of five, B has been best friends with Motoi, whom he always greeted with a fist bump. After his cousin, the jinchūriki of Gyūki lost control and killed Motoi's father along with seven other ninja on that day, B was chosen as its next jinchūriki. Soon afterwards, B suffered from similar prejudices against jinchūriki, not too different from that the villagers of Konohagakure and Sunagakure had against Naruto Uzumaki and Gaara respectively.

However, he kept smiling and pushed himself to be the best jinchūriki that he could be, so that his brother wouldn't be hurt politically as the Fourth Raikage.

After his father's death, Motoi tried to kill B, believing it would also kill Gyūki and avenge his father, but B disarmed him easily, and despite the attempt on his life, bore him no ill will, which led Motoi to not speak to B for thirty years out of shame. B would later train with his brother on an island in the Land of Lightning, where there he would find the Falls of Truth. There he learned how to control Gyūki in the blink of an eye. Some time after his training, B, alongside A, and other Kumo shinobi confronted Minato Namikaze and his small squad. When Minato moved to counter A's attack, B used a tentacle to push A out of the way, causing shock to the Konoha shinobi that he was Gyūki's jinchūriki. Some time since then, much like Naruto, B has become beloved in Kumo as the village's hero, or, as Motoi called him, the "Hero of Heroes".

When A became the Raikage, he forbade B from fully transforming into the Eight-Tails and restricted him from leaving the village, saying instead that he would become the guardian of the village and attack from within its walls.

Personality
Killer B is very proud of his own power and very proud of who he is. Like Naruto Uzumaki, who has great overconfidence, Killer B, can be quite cocky and stubborn, especially in terms of his own strength, demanding respect from others and asks to be called and his tailed beast be called. B has a special way of expressing his pride through song, more specifically in rap-style and tends to use when referring or speaking to others. He will even write his rhymes in the middle of a fight, or during an important meeting, even if they are no good, which is usually the case. This sometimes causes the people around him to become greatly annoyed by him. B doesn't respect anyone who would make fun of rap or his lyrics.

The Raikage has noted that Killer B is not the type of person to work with the strategies created by people and that he would only bring chaos into a battlefield; in his youth he was already seen completing missions, that were supposed to be assigned for both him and his brother, without A's knowledge. The Raikage also notes that he is the only being that B will listen to, as he is able to keep him in check. Despite all this, B knows talent when he sees it, and respects those with it. The primary example is his fellow Kumo jinchūriki, Yugito Nii, who he looked up to for her extreme skills. He had also praised Sasuke after their fight, stating he was one of the strongest shinobi he had ever fought. B has a very close relationship with his older brother, the Raikage. According to Motoi, the reason behind him becoming a jinchūriki was for the sake of his brother, even if it meant being shunned by the villagers. He didn't complain, and was always cheerful and determined.

Due to the fact that he was confined to the village very soon after his brother assumed office and made the village's guardian, B desperately wished for a vacation and was even ready to fake his capture for one. When the Fourth Raikage, Darui and C learned that B was not captured by Akatsuki, they immediately guessed his intentions and were not surprised by it, though they were very displeased. This lead to him receiving his brother's "Iron Claw" as punishment. B also tends to fist bump with others. This ties into his rapper personality and also serves as a means of communication of sorts, with others without the need to speak.

However, when someone close to him is in danger, Killer B has no qualms about putting himself at risk to save them, if necessary, as seen when he prioritised the safety of his singing master Sabu and his pet, Ponta over confronting Kisame head-on when the Akatsuki confronted his entourage. This caring nature differentiates him from a typical jinchūriki, most of whom are cynical and uncaring towards others due to their circumstances. However, it was hinted that his past as a jinchūriki may not have been unlike Naruto's, since Motoi claimed that being a fellow host, B understands what Naruto went through. He has a casual relationship with Gyūki, frequently engaging in friendly conversation with it, even sitting upon its nose at one time. He was also completely unaffected by Naruto's Harem Technique, resisting lustful advances and even appearing indifferent. Naruto stated that B is the first man to resist this technique. However, he is not completely unaffected by such things, as he noticed Tsunade's rather sizeable cleavage, which his brother reprimanded him for and he later stared at Yugito's own sizeable bust when it was shown during his fight with Tobi's Six Paths.

B is also very kind and compassionate, having befriended all the giant animals on the Island Turtle which may indicate that he has a liking for animals, as well as never expressing any ill will towards Motoi who tried to take his life, nor against the villagers who used to shun him.

Appearance
Killer B has dark-skin and a muscular build, as well as white hair (blond in the anime) and a goatee. On his right shoulder, he has a tattoo of the kanji for, which is the Iron Armour Seal that was used to seal Gyūki into him, and on his left cheek, he has a tattoo of a bull's horn (correspondingly, the Gyūki has horns like a bull, and the left one is partially missing). His top lip also has a slightly darker hue than his bottom one.

Killer B wears oval shaped sunglasses and a white coloured forehead protector. He also has his village's standard one-strap-over-one-shoulder flak jacket, and a long, red rope belt tied around his waist, the standard Kumo hand and shin guards, shinobi sandals, and a white scarf around his neck. He originally carried seven swords on his back, but now only carries two swords on his back and stores the rest inside Samehada.

As a child, B's hair was much shaggier and he wore a simple suit along with his trademark sunglasses and scarf along with Kumo-nin shin-guards. In his adolescent years, his hair grew much longer and he wore it in a stylised, combed-back manner. In these years he donned the standard uniform of the Kumo-nin inclusive of shirt and started carrying two Supervibrato Lightning Release Swords. As he got older, he started wearing his forehead protector like a bandanna.

Abilities
As the guardian of Kumo and Gyūki's jinchūriki, Killer B is an extremely powerful ninja, capable of overwhelming the entire team Taka all by himself, and has had his skills praised by several Kumo-nin, including his older brother. Even as a child, B showed promising skill, being able to accomplish missions all on his own, despite the fact that they should have been executed as a team, with A as his partner. Tobi claimed that he is the perfect host, a statement later reaffirmed by Kisame. As expected of a jinchūriki, B has a very large reservoir of chakra, enough to make Samehada get very excited and betray Kisame. During his time on an island where he trained to control Gyūki's power, B tamed almost all of the island's beasts. A claimed that B had more talent than he did.

Killer B possesses sharp wit, as shown when he used the Body Replacement Technique to switch places with Gyūki's tentacle so he could escape Sasuke Uchiha's Amaterasu. He also has the ability to interpret someone's "heart" as well as transmit his own feelings merely through touching someone (which is usually done through a fist bump). This ability was first demonstrated when he was training with Naruto in the Tailed Beast Temple, again when Iruka expressed his wishes to protect Naruto to him and when he stopped his brother from attacking Naruto. B is also quite knowledgeable in fūinjutsu, able to distinguish between the superiority of the Four Symbols Seal to his own Iron Armour Seal.

Taijutsu
B has immense physical strength and combat prowess, capable of fighting on equal ground with all three male members of Taka at once, despite all three being dangerous fighters, while still holding back, as well as winning a sumō match against a giant bear. Even as a young boy, he was the the only person to successfully perform a Double Lariat with A, allowing him to become the future Raikage's tag-team partner. During the Fourth Shinobi World War, it was seen that B's Lariat is stronger than that of his brother's, not even needing Gyūki's chakra to overpower him despite A being clad in his lightning armour. He has shown incredibly fast reflexes, enough to intercept Minato Namikaze's kunai with one of Gyūki's tentacles, as well as being able to quickly react to Sasuke Uchiha attacking him at close range and block and repel him with a single move. B is also immensely fast as when Jūgo attacked him, B was able to instantly dodge his attack and make it to another mountain before Taka even saw he was gone, requiring Karin to locate him.

B is also incredibly durable in battle, having received a solid kick to the neck from Sasuke Uchiha only to drop his sword and begin writing lyrics, escaping unscathed after being hit by the electricity of Sasuke's Chidori, and blasted from behind with a powerful punch from Jūgo. He could take one of A's Lariats straight to the chest with no visible damage. Killer B has a fighting style which is similar to that of the Raikage's because they both use wrestling moves instead of standard taijutsu. He supplements the speed and power of his taijutsu with his tailed beast's cloak.

Kenjutsu
While originally only carrying two swords when he was young, B has developed his swordplay to an incredible level. Possessing a unique fighting style, B holds his seven blades in between the joints of his arms (left armpit, both elbows), right leg, stomach, the right side of his neck, and in his mouth. As strange as it appears, B is very skilled with this. Because of the unpredictability of his movements, his opponents are easily overwhelmed with all of the varying swings, giving him great versatility very similar to hip-hop dance. When he finds an opening, B can impale his opponent with most of his swords quickly and simultaneously.

Neither Suigetsu Hōzuki, a highly trained swordsman, nor Sasuke Uchiha, a Sharingan user, could read his swordplay. He is capable of cutting through almost anything when he flows his lightning chakra through his blades. B can also use these blades as mid-range projectiles. By covering himself with Gyūki's chakra, he creates an "Eighth" sword. After obtaining Samehada, B intended to use it as his main weapon. He has integrated Samehada into his fighting style taking advantage of the sword's ability to 'cut' chakra, allowing him to bisect Itachi's Fire Release: Great Fireball Technique. Samehada and B are capable of working in tandem; while it attacks the enemy on its own, B attacks them from a blind spot.

Nature Transformation
Killer B has displayed the ability to flow lightning-natured chakra through his blades to increase their cutting power. B's prowess in Lightning Release techniques is so great, he can charge a sharp but weak pencil-point to pierce straight through a large tree trunk and even through the ground. As stated by Kisame, B is able to do this by increasing the vibration frequency of his lightning chakra to surpass the standard penetrative force of wind chakra.

Jinchūriki Transformations
Killer B is one of the few people to have achieved full control over a tailed beast as noted by Danzō Shimura. He is also one of the three jinchūriki to have done so, the others being Yagura and Naruto Uzumaki. B, however, is the only living jinchūriki who can retain his full tailed-beast form indefinitely while Naruto can currently only stay fully transformed for five minutes at a time. Like other jinchūriki, B has the ability to create a chakra cloak by drawing on part of his demon's power. He can then form this chakra into the form of two horns, and use them to attack the enemy with a technique called Lariat. This attack has incredible speed and power, but the linearity of his movements makes him easier to predict. Because he has a strong relationship with his own tailed beast, it acts as his partner in battle, disturbing his chakra to dispel even genjutsu from the Mangekyō Sharingan. This makes B's "control" over Gyūki more of a willing partnership than actual control.

Like his fellow Kumo-nin, Yugito Nii, B is able to transform into his tailed beast with great ease, reaching a full transformation in mere seconds. Unlike Yugito, however, he can retain complete control even in this fully released state. B can also partially transform parts of his chakra shroud into parts of the Eight-Tails' body. When fully transformed, he can easily fire a Tailed Beast Ball many times the size of its already giant body, but B was forbidden from transforming by A. B makes it a point to ignore this order when he can, either when training or to fight formidable opponents. While in full Eight-Tails form B can spin to summon up a great force of wind that can destroy an entire forest with ease.

B's skill with partial transformations is such that he can form all eight tentacles on his back without a cloak, and use them to stack and balance various blocks perfectly. He can form tentacles very quickly allowing him to intercept fast opponents, or have them burrow through the ground and catch an opponent off guard. B can transform one of his arms into that of Gyūki's to use for various purposes such as throwing Might Guy a long distance away or blocking attacks. Similar to how other jinchūriki obtain physical traits from their inner beast, B is able to produce ink from his mouth, which he mainly uses to write lyrics when he is lacking of regular writing tools or to blind his opponent. This ink can be used in a more solid form to make ink clones which immobilise his enemies through wrestling locks. After the opponent is captured, the clones proceed to trap and seal them.

Invasion of Pain Arc
While leaving the Valley of Clouds and Lightning after training, B was confronted by Taka. He was immediately attacked by Suigetsu, whose sword B took and used to overpower Jūgo. Sasuke Uchiha then stepped in and used his own sword to take back Suigetsu's. Impressed, B bought out his seven swords and attacked Sasuke, his unorthodox fighting style preventing Sasuke from tracking his movements with his Sharingan. Sasuke tried to gain the upper hand by channelling lightning through his sword, but B did the same with one of his swords, removing the advantage, and plunged the other six into Sasuke's torso, fatally wounding him.

Before he could finish off Sasuke, Suigetsu and Jūgo came to his defence. B was able to damage Suigetsu's sword but Taka was also able to force him back. Sasuke was healed by Karin and the fight continued. B became bored with the fight and tried to leave, but was tracked by Karin. With escape not an option, B entered his Version 1 form and attacked Taka. Taka was able to elude him and Sasuke caught him in a genjutsu, which Gyūki helped B break out of, allowing B to hit the unaware Sasuke with a Lariat, blasting a hole in Sasuke's chest, again mortally wounding him. Deciding to finish things off, B fully transformed. He fired a Tailed Beast Ball, which Suigetsu was able to protect the rest of Taka from by using himself as a shield.

Sasuke, specially healed by Jūgo, used Amaterasu on B. B rampaged in pain and almost crushed Karin with one of his tentacles. Sasuke severed the tentacle, and B used the opportunity to escape and fake his capture, by substituting with the severed tentacle, allowing him to leave the village. Taka were unaware of this, and delivered "B" to Akatsuki. While later trying to extract Gyūki from this B's body, Akatsuki discovered that this was a fake.

Five Kage Summit Arc
Free from his confinement to Kumogakure, B sought out Sabu to advance his music career. In the midst of training B was found by Kisame Hoshigaki, who tracked his powerful chakra with his Samehada. While Sabu attacked him, B struck from behind with one of his lightning-imbued swords. Not only was Kisame able to block their attacks with Samehada, but B's lightning disappeared when it makes contact. B entered a Version 1 form and attempts to Headbutt him, but his chakra shroud disappeared too. Sabu realised that Samehada was absorbing B's chakra.

B entered an seven-tailed Version 1 form and attacked Kisame again but Samehada absorbs most of his chakra. Upon realising that Samehada could only absorb six tails at a time, B entered a Version 2 form and created chakra-bones to use in a more powerful Lariat. Kisame was badly damaged and Samehada was only able to absorb his Version 2 chakra, returning B to a Version 1 form. Samehada used the chakra it absorbed from B to heal Kisame, who quickly merged with Samehada and created a dome of water around them. B tried to get Sabu and Ponta out of the dome before they drown, but the water dome moved with Kisame. B drew Kisame away from Sabu and Ponta, in order to force him to release them to pursue B. Once they were free, B confronted Kisame, only for Kisame to render all of B's counterattacks ineffective and slowly absorb his chakra all the while.

When B lost consciousness, Kisame dissipated the water dome. To prevent B from escaping, Kisame tried to cut off his legs with Samehada. However, Samehada had grown fond of B's tailed beast chakra during the battle and betrayed Kisame; in addition to not letting Kisame harm B, it transfered some of the chakra it stole back to him. Kisame kicked it away and tried to cut off B's legs with one of B's own swords, but the Raikage and his bodyguards arrived to stop him, having noticed Kisame's water dome. Samehada continued to replenish B's reserves, allowing B and A to perform Double Lariat to decapitate Kisame. A then reprimanded B for running away from the village.

When they returned to Kumogakure, B now carrying Samehada, they were greeted by the villagers at the main gate. B's students, Omoi and Karui, ask about Samehada, which he has taken back with him. They and B were unaware that Kisame, having faked his death, was hiding inside Samehada to gather intel on Kumo and the Shinobi Alliance during the meetings B later attended (and didn't pay attention to).

Confining the Jinchūriki Arc
When the Fourth Shinobi World War breaks out, the Alliance decides to send the remaining jinchūriki to the Island Turtle to hide. B gets there first, allowing him to defend fellow jinchūriki Naruto Uzumaki from the Giant Squid when he arrives. Because he never got much of a vacation while away from Kumo, B tries to enjoy himself by relaxing and spending time with the island's animals. During this "vacation", Naruto approaches B and asks for help gaining control of the Nine-Tails. B senses an evil within Naruto so declines until he can deal with it. Later, when the squid attacks Motoi, B comes to his aid. Motoi apologises for trying to kill him years earlier and B does not hesitate to make amends.

The reunion between B and Motoi shows Naruto how to overcome his inner hatred. With it vanquished, B takes him to the secret temple behind the Falls of Truth where B shows him how to enter his subconscious and confront the Nine-Tails. When Naruto first breaks the seal and releases the Nine-Tails, B tries to help him contain it. His abilities are limited while in Naruto's subconscious and he is only able to block a tailed beast ball from the Nine-Tails before being knocked out of the fight. Naruto emerges victorious and communicates all that he went through to B with a fist-bump. Naruto then demonstrates his new control of the Nine-Tails, allowing him to expose Kisame's presence.

Kisame flees with Samehada and B pursues him. Samehada tries to return to B, allowing Kisame an opportunity to absorb his chakra. When he recovers, B flings Might Guy after Kisame. Guy is able to capture him but Kisame commits suicide. They try to check the intel Kisame had with him, but it is booby-trapped and they are imprisoned while a shark swims away with the intel. B tries to catch the shark after he frees himself, but is unsuccessful. Fearing an imminent Akatsuki attack, the island's animal population is moved indoors. Because Naruto is not to know about the ongoing war, B helps keep Naruto distracted while an Akatsuki attack occurs outside.

Shinobi World War Arc
B starts helping Naruto gain control of his new Nine-Tails Chakra Mode, first by having him use his chakra arms to stack blocks in a perfect column. When Naruto masters this, they move on to transforming into the Nine-Tails. The Nine-Tails will not cooperate with Naruto on this, leaving him unable to use the Tailed Beast Ball. They instead decide to practice with Naruto's standard technique to see how the Nine-Tails' chakra affects them. Naruto begins with his Rasengan, which B recognises as being based on the Tailed Beast Ball. B encourages him to focus on mastering the Rasengan in this new form.

During training, Naruto senses some of the Nine-Tails' chakra elsewhere. B tries to convince him that it's nothing, determined to keep Naruto in the training room so he doesn't find out about the war. He nevertheless lets Naruto leave to go to the bathroom. B goes looking for Naruto when he doesn't return. He instead finds Iruka Umino, who requests that B protect Naruto. Recognising Iruka as a positive influence from fist-bumping with Naruto, B agrees. He catches up to Naruto and the two team up to break through the Thirty-Six Layer Self-Repairing Barrier to escape from the island. They then head for the battlefield.

While en route, they are intercepted by A and the Fifth Hokage. B tries to convince his brother to let them pass, promising to keep Naruto safe from Akatsuki. A is not convinced by his words and, when Naruto promises to use force to escape, the Raikage threatens to kill him. B blocks the latter's attack and informs his brother that he must be willing to kill both of them. He claims to have no problem with this but B, unbelieving, bumps fists with him to remind him of all they've been through together. Still unconvinced, both he and Naruto try to combat him but struggle doing so as A manages to fight them off. B and A simultaneously hit each other with their respective Lariats and B's overpowers his brother's.

Later on, B explains how he overpowered A with his Lariat. A pushes B out of the way and activates his Lightning Release Armour again, B noticing his intent to kill. B is impressed when Naruto dodges A anyway. A is also impressed and lets them pass. While en route they encounter several shinobi one of which included F who tells B that they had to return to headquarters as back-up. Before he can continue however, Naruto attacks him revealing that he was a transformed enemy much to B's shock. Naruto then tells him that they're all enemies and he could go all out. Later after taking out a few of the clones, B watches on with amazement and pride as Naruto takes out the enemy, while noting that the Zetsu were turning into trees in the same manner Yamato's wood creations did at the Tailed Beast Temple. Later while Naruto arrives just in time to save two shinobi from Toroi's onslaught, he has a conversation with one of his fellow Kumo-nin before setting out once again. While en route with Naruto, the two encounter Itachi Uchiha and Nagato.

As the battle commences suddenly with Itachi being forced to use the Fire Release: Great Fireball Technique, B uses Samehada to slice through the attack effectively saving both him and Naruto. However, Samehada accosts B telling him that the flames were extremely hot for which B apologises. As Itachi appears behind B suddenly and uses the Fire Release: Phoenix Sage Flower Nail Crimson technique but is countered by B's transformed arm. B then uses the tentacle he sent underground to grab Itachi who disappears in a flurry of crows. As Itachi tells B not to look into his eyes, Gyūki breaks B out of the genjutsu he had already been caught in. He then calls for Samehada, from which B gets his other five stored swords and then charges Itachi using his seven swords. Itachi retreats onto Nagato's summoned bird.

As Itachi activates his Mangekyō Sharingan B tries to stop him by throwing his sword but it is repelled by Nagato. Itachi uses Amaterasu on Nagato and his summons. Itachi then explains to Naruto and B why the crow has a Mangekyō Sharingan and how he got it. Nagato, now recovered and being completely controlled by Kabuto now, sneaks behind them with his chameleon summon and uses Shinra Tensei to attack Killer B and Naruto. Nagato appears behind B and tries to attack him, but B goes into his Version 2 transformation and counters Nagato's attack with a Lariat. Nagato uses the Preta Path's ability to absorb B's chakra which leads Nagato to regain a youthful appearance.

Seeing Naruto in dire straits with his soul being removed, B moved to attack Nagato. Nagato, sharing vision with his own chameleon summon and the King of Hell, intercepted B by using his Asura Path abilities. Before Nagato can fatally injure B and remove Naruto's soul, they are rescued by Itachi's Susanoo. As Nagato uses Chibaku Tensei in an effort to trap them, Itachi tells them to attack the centre of the sphere in an attempt to dispel the technique. With the combined force of B's Tailed Beast Ball, Itachi's Yasaka Magatama and Naruto's Wind Release: Rasenshuriken, the sphere is dispelled. B watches on as Itachi's Sword of Totsuka begins to seal Nagato who passes on his final words to Naruto, who then passes onto the afterlife.

After Itachi claims that he will stop the Summoning: Impure World Resurrection technique, B voices his doubts and recalls that they were not able to kill the resurrected ninja, just seal them. Itachi reminds them again that no matter how infallible a technique may seem, it has a weak point. As Naruto states that he would end the war, that they should leave everything to him and attempts to create shadow clones he reverts to his normal self. B tells him that he had used up too much of the beast's chakra and that he shouldn't make any more clones for a while. After Itachi tells him not to try to shoulder everything himself, B reminds him that he had made a promise to Iruka and he wasn't dead yet so he would help. B is later scolded by Gyūki for taking too long to urinate and for letting Naruto go ahead of them. When Naruto's clone contacts them mentally, he asks B to let him speak to Gyūki to which B refuses while urinating. However, the clone still gets to speak to the beast because it could overhear mentally. Afterwards, he catches up to the real Naruto and informs him that he had been contacted by one of his clones. B then asks him what was going on with his other clones. Later, B and Naruto run into Tobi with his Six Paths of Pain.

Catching Naruto as he recoils from the impact, he tells him to calm down as they both proceeded to engage the revived jinchūriki. Manoeuvring through Rōshi's stream of molten rocks, they are then attacked by doppelgänger created by Yagura, before being sent flying backwards from the explosion and into a field of Utakata's explosive bubbles. Partially transforming into Gyūki, B is able to save himself and Naruto from the effects of the technique only to be caught in Fū's technique which shrouded incoming attacks from both Yugito and Han. As he parries Yugito's attack, he states that his glasses were way too dark to be blinded by an attack like that. Conversing with Gyūki about the jinchūriki and Yugito's fate, B enquires about the "other Madara" that Naruto was speaking of. Looking on smiling as Naruto retorts, telling Tobi that it wasn't all bad living with a tailed beast inside them, he declares that he would go first before staring in shock as the other jinchūriki begin their tailed beast transformations.

Shocked that they still had their tailed beast skills, B attacks Fū head-on nonetheless. After she dodges several of his and Samehada's attacks, Naruto informs him of the shared field of vision that the Six Paths of Pain possessed using the Rinnegan. Catching Naruto, B flees the vicinity after seeing Yugito unleash her Mouse Hairball technique. Clashing with her while escaping, he is able to land a somewhat shallow attack on her that immediately begins repairing. This opportunity however, allowed B to see where Tobi had implanted the chakra receivers in his Six Paths. After Naruto's attempt to destroy the receivers in Rōshi's chest is thwarted, B agrees with Gyūki that the forest was too much of a hindrance for them and transforms into Gyūki to level the entire forest.

Grabbing Naruto in his hand, B begins to spin in a gigantic circle generating gale-force winds which effectively level an entire area of the forest. B immediately moves to seal the revived jinchūriki with his Octopus Hold technique but it is unsuccessful as Tobi causes the jinchūriki to enter Version 2-like states. As they begin counter-attacking, B and Naruto try to fend them off, but begin feeling the pressures of fighting six powerful opponents. B is attacked by a fully transformed Han, who gores him with his horns and sends him flying, seemingly knocking him unconscious. After B comes to, he asks Gyūki if it was all right to which it replies that they were both wounded. After Tobi lost total control over the Five-Tails and restrained it with a chakra chain, B attempts to crush him within Gyūki's fist, but Tobi simply slipped trough it. As the Five-Tails is being subdued, B and the Eight-Tails asks Naruto if he had also heard Five-Tails' voice and the Eight-Tails then laments that seeing other tailed beasts treated that way naturally annoyed the rest of them. While Gyūki and the Kurama are talking telepathically, Naruto suggests using shadow clones to create a diversion and allow them to strike Tobi, B urges Naruto not to as he would die due to the Nine-Tails sucking away his chakra. However, Gyūki reveals that the Nine-Tails had seemingly stopped doing this for some time now due to Naruto's stable condition after using so much of the beasts' chakra. He then gets tossed away by a fully transformed Rōshi. B is later impressed when Naruto manages to escape Son Gokū's stomach using shadow clones.

After Naruto successfully removes the chakra receiver, B watches on with shock as the beast is resealed into the Demonic Statue of the Outer Path in the blink of an eye. As Naruto rallies, telling the beast and B to get ready, it tells him that he and B would be taking to front-line while Naruto acted as support because he was still unable to transform into the Nine-Tails. After Naruto tells them it'd be fine because they were a pair of duos, he wonders whether Kurama had finally come around. As the battle begins, to B's astonishment, Naruto assumes the form of his tailed beast before joining the fray. He then stops the Three-Tails who was planning to attack Naruto while he was incapacitated by the Six-Tails. After the Three-Tails frees itself from Gyūki's tentacles, they watch on as the five beasts prepare a collaborative Tailed Beast Ball and Naruto prepares to negate the attack with one of his own. As Gyūki wonders if Naruto would be able to do it, B tells it that he almost did it during his training, but is sure that Naruto will be able to do it now.

As the two Tailed Beast Balls collide, B grabs Rōshi's body and protects himself from the after-effects of the attack as he notes that Naruto hit the base of the other attack allowing it fly into the air. He later congratulates Naruto on freeing the other beasts, before advancing behind Naruto, Guy and Kakashi, preparing to fight Tobi directly. Later, as Naruto mocks Tobi with the information he had just learned, B looks on smirking.

Creation and Conception
Masashi Kishimoto in a 2012 Shōnen Jump interview, stated that one of his past editors who really likes pro wrestling greatly influenced his decision to create a character that — even though he was a shinobi — used pro wrestling moves as part of his techniques. He also stated that he wanted to make him into an interesting character and one of the most powerful shiniobi in the series. Kishimoto went on to say that he has trouble writing B's lines at times because he always wants them to rhyme due to his rapping style.

Trivia

 * His name is a reference to the famed rap group, the Wu-Tang Clan, often referred to as the "Killer Bees".
 * Bī is the Japanese pronunciation of the letter "B" (as well as the Japanese pronunciation of "Bee"). This parallels the names of other Kumogakure shinobi such as F and J for example.
 * During a fierce battle with Taka, B quoted Muhammad Ali's famous line, "float like a butterfly, sting like a bee".
 * Killer B makes various references to bees. This is a pun on the number of tails his tailed beast has. Eight in Japanese is, a homophone to the Japanese word for bee,.
 * Though not confirmed, Killer B was given the name of Kira Hachi by fans. It comes from the word "Kirābī" incorrectly translated into Japanese (Hachi is the Japanese word for "bee", as well as "Eight". Kira is a loanword of the English "killer"). Kira Hachi, can be translated to "Killer Eight", following the homophone of bee.
 * B's nickname may be a reference to The Killer Bees, a professional wrestling team in the World Wrestling Federation. Additionally, the Double Lariat resembles the "Cross Bomber" move used by the Hell's Missionaries tag-team in Kinnikuman, a wrestling manga.
 * B has used or has possession of two of the Seven Swordsmen of the Mist blades so far. He used Zabuza Momochi's Kubikiribōchō in his fight with Taka and he has taken possession of Kisame Hoshigaki's Samehada.
 * In chapter 542, when A and B face off against several Iwagakure shinobi while on a mission, B is first depicted with longer hair and looks a bit older. However, in subsequent panels his hair is once again short and spiky and looks much younger. Oddly, this was not corrected in the tankōbon.
 * In a 2012 Shōnen Jump interview, Masashi Kishimoto stated that Chōji Akimichi and B were currently his favourite characters in the Naruto series.

Quotes

 * "I'm the only one who gets to interrupt me!"
 * "I've got energy to spare and sparkling charm. The Eight-Tailed Beast's a killer bee rockin' the melody! OH YEAH!"
 * (To A) "Becoming a jinchūriki, you can lose a lot, and your heart goes hollow, but if you got things you don't want to lose, they become a light to follow! The tailed beasts aren't our only source of strength! What was inside our hearts before the monster... shines like a sun, powers us to any length! That's where our true power comes from!"
 * (To A) "Brother, I'm a big idiot as you said too, and Naruto is as well, right dude? But the ones who accomplish things are the big idiots that don't care about how thick and strong the wall is, yahoo."
 * (To A) "Brother, I'm a big idiot as you said too, and Naruto is as well, right dude? But the ones who accomplish things are the big idiots that don't care about how thick and strong the wall is, yahoo."