Killer B

is a muscle-bound shinobi from Kumogakure and the Jinchūriki of the Eight-Tailed Beast. It is hinted he comes from the Yotsuki clan. He appears to dislike light. On his right shoulder, he has a tattoo that says ; and on his left cheek, he has a tattoo of a bull's horn (correspondingly, the Eight-Tails has horns like a bull, and the left one is missing). He also carries seven swords and has a brother who is the Raikage.

Personality
It seems that he demands respect from others and asks to be called and his Tailed Beast be called. He also appears willing to speak in song, more specifically in rap style, even when confronted with potential threats. He will even stop in a middle of a fight to write whatever rhymes come to him, even if they are no good. This sometimes causes his opponents to become greatly bothered by him. He has a casual relationship with the Eight-tailed Beast, frequently engaging in friendly conversation with it.

Hunt for the Eight-Tails
Team Hawk, after discovering that the Eight-Tails was training in the Valley of Clouds and Lightning, traveled up to the valley. He revealed himself after appearing to contain his Tailed Beast. When Suigetsu attacked him, he easily overpowered him, and uses Suigetsu's sword to defeat Jugo afterward. He later shows an unorthodox sword style where he manages to hold all seven of his swords in a rather awkward pose, this is deceiving as his seven sword style is extremely formidable and he even fatally wounds Sasuke Uchiha as Sasuke could not track the sword movements even with his sharingan.

As he moves in to finish Sasuke, Suigetsu comes to save him while Jugo attacks from behind. Even with the three fighting him at once Kirābī appears unphased by their attacks. When the three do a triple damaging attack to him, he somehow moves extremely quickly to a safe position relatively far away. Finally getting annoyed with Team Hawk, Kirābī decides to go home and have some whiskey, but Karin senses his location. As Sasuke is rocketed to his position, Kirābī announces he will unveil the "Eight One". Kirābī developed his own demon chakra shield, similar to Naruto's chakra shield, and proceeded to attack Team Hawk. Sasuke then attempted to place him in a genjutsu but as Sasuke lowered his guard, Kirābī struck. In the end, he blasted a hole in Sasuke's chest and neck claiming that a Jinchuriki that has full control of his beast can become immune to genjutsu. Annoyed with Team Hawk, he finally completely released the full power of the Eight-Tailed Beast, ordering the team to cower in fear of him, something they did.

After the Eight Tails was hit with Sasuke's Amaterasu, it transformed back into an unconscious Kirābī. With his defeat, Sasuke carries him away. After Kirābī is kidnapped, his brother, the current Raikage, is inadvertantly outraged. He sends out some Cloud Ninja to stalk Team Hawk. The first one, Jei, is captured by Sasuke and Jugo (it is unknown if they killed him or not). Three more are sent out after him. This second team includes Samui, Omoi, and Karui. These three are apparently his students.

"Vacation"
While sealing the Eight-Tailed Beast, Kirābī's body transformed into the tentacle that Sasuke had severed during the fight. It is revealed that the real Kirābī had replaced himself with that tentacle and used the entire fight as a ruse to escape his village, where he had grown bored of being a guardian. Since his village now believes him to be captured, he uses this as an opportunity to take a "vacation" from being a guardian. As Eight Tails comments that a new era is coming, Kirābī thinks he means about his new music career.

Abilities
His physical strength and taijutsu skill is immense. He is easily capable of disarming a skilled opponent with his bare hands, and proficiently wielded Suigetsu's huge sword seconds after picking it up. His specialty, however, is wielding his seven swords, which he does in an odd way, holding them in between the joints of his arms and left leg, his stomach and the left side of his neck and in his mouth. As strange as it appears, he is quite skilled with this, spinning around like a buzz saw and overwhelming his opponent with all of the varying swings. He is also capable of seamlessly releasing some of the swords to fight in a more conventional style, giving him great versatility. When he does find an opening, he can impale his opponent with most of his swords at once. Neither Suigetsu or Sasuke could read his swordwork, despite one being a highly trained swordsman and the other possessing a Sharingan.

During the battle with Sasuke he displayed the ability to flow lightning-elemental chakra through his blades to increase their cutting power, similar to the Chidori Current Sasuke uses with his Kusanagi Sword. His defense is very strong as well, receiving a solid kick to the neck from Sasuke only to drop his sword and begin writing lyrics, and escaping unscathed after being shocked with Sasuke's chidori and hit from behind with Jugo's rocket-augmented attack.

Like Naruto, Kirābī also has the power to create a chakra cloak by drawing on part of his demon's power, which he refers to as his "8th tail". In this state he 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 Sasuke's high-level Mangekyo Sharingan genjutsu. Like his fellow Cloud shinobi, Yugito Nii, he is able to become his Tailed Beast itself with great ease. The Hachibi can easily and repeatedly fire massive chakra blasts many times the size of its already giant body, but Kirābī was forbidden from transforming by the Raikage.

Trivia

 * His Sword style is reminiscent of Roronoa Zoro's Santōryū in One Piece (a fellow Shonen Jump manga) in that he uses an odd number of swords as well as holding a sword in his mouth.
 * He quoted Muhammad Ali's famous line, "float like a butterfly, sting like a bee".
 * Though not his confirmed name, Kirābī was given a fan name of Kira Hachi, the word "Kirābī" incorrectly translated into Japanese (Hachi is the Japanese word for "bee". Kira is a loanword of the English "killer").
 * Kirābī has a unique personality, similar to black urban youth stereotypes (corn rows, jive talk, and rapping). This could also either be a homage or a reference to the Wu-Tang Clan, who are martial arts enthusiasts. He calls himself the Kirābī - an old "Wu Tang" Kung Fu movie and group name of Wu Tang Records. Most members and groups of this label get their stage name from the old "Wu Tang" movies (Ex. Method Man, Old Dirty Bastard, RZA, GZA, Kirābīs, and the records labels name itself).
 * Kirābī 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,.
 * As a unintentional pun, the fan name Kira Hachi, can be translated to "Killer Eight", following the homophone of bee.
 * Unlike Naruto and Gaara, Kirābī has a good relationship with his Tailed Beast.

Quotes

 * "I was right in the middle of an announcement, you stupid idiot!"
 * "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 killerbee rockin the melody! OH YEAH!"