Killer B

is a black, musclebound shinobi from Kumogakure and the Jinchūriki of the Eight-Tailed Beast. He appears to dislike light. On his right shoulder, he has a tattoo that says "iron"; and on his left cheek, he has a tattoo of a bull's horn (ironically, the Eight-Tailed Beast has horns like a bull, and the left one is missing). He also carries seven swords.

Personality
It seems that he demands respect from those under him and asks to be called "Mr. Jinchūriki" or "Mr. Eight-Tails". 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.

Hunt for the Eight-Tails
Team Hawk, after discovering that the Eight-Tails was training in the Unraikyo Mountains traveled up the mountain. 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 afterwards. He later shows an unorthadox 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 he moves in to finish Sasuke, Suigetsu comes to save him while Jugo attacks from behind. Even with the three fighting him at once Kira appears unfazed by their attacks. When the three do a triple damaging attack to him, he somehow moves extremely quickly to a same position relatively far away. Finally getting annoyed with Team Hawk, Kira decides to go home and have some whiskey, but Karin senses his location. As Sasuke is rocketed to his position, Kira announces he will unveil the "Eight One". Kira Hachi developed his own demon chakra shield, similar to Naruto's chakra shield, and proceeded to attack Team Hawk. Sasuke then attemped to place him in a genjutsu but as Sasuke lowered his guard, Kira 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.

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 giant 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. As awkward as it appears, he is quite skilled with this, spinning around like a buzzsaw 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. While fighting with this style, he was effortlessly able to defeat Sasuke and would have killed him if not for Karin's healing abilities. He has a very strong defense, as seen when Sasuke nailed him with a fully powered Chidori, and also when Jugo slammed him in the face with a curse seal powered arm only to have him say "Those weaklings are really annoying".

During the battle with Sasuke he displayed the ability to conduct chakra down his blades to increase their cutting power like Chidori Current does with Sasuke's Kusanagi Sword. He is able to conduct his own lightining element chakra into his swords and give an electrifing blow.

Like Naruto, Kira Hachi also has the power to create his own chakra shield when drawing on his demon's power without much effort. It is because he has control over his own demon, he is able to break Sasuke's Mangekyo Sharingan genjutsu because he used the Eight-Tails to disturb his chakra. Like his fellow Cloud kunoichi, Yugito Nii, he is also able to become the Eight-Tailed Beast itself with great ease.

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" in chapter 411.
 * Though not his confirmed name, Kira Hachi is the fan name given to this Jinchūriki (the other being "Mr. Eight-Tails"). Also, it is hinted he hails from the Yotsuki clan.
 * Kira Hachi has an unusual personality, similar to African American 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 Killer Bee - 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, Killer Bees, and the records labels name itself).
 * He is currently the only person of color in the series.