Killer Bee

キラービー

When young, B and several other children were gathered to select a tag partner for A. Among all the children present, B was the only one capable of successfully executing the Double Lariat with A. Consequently, he was given the name "B," and A declared they would be brothers from that day forward. After A's cousin, the jinchuuriki of Gyūki, lost control and killed Motoi's father along with seven other ninja on that same day, B was chosen as the next Jinchuuriki at the age of 5.
During the 3rd Great Shinobi World War, he and his brother encountered Minato Namikaze and had a minor scuffle with Minato and his squad.
Killer Bee is a muscular shinobi from Kumogakure and the Jinchuuriki of the Eight-Tailed Beast. It is hinted that he comes from the Yotsuki clan. He appears to dislike light. On his right shoulder, he has a tattoo that says "iron" (鉄, tetsu); 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.
It seems that he demands respect from others and asks to be called "Lord Jinchuuriki" (人柱力様, Jinchuuriki-sama) and his Tailed Beast be called "Lord Eight-Tails" (八尾様, Hachibi-sama). He also appears willing to speak in song, more specifically in rap style, even when confronted with potential threats. He will even stop in the middle of a fight to write whatever rhymes come to him. He has a casual relationship with the Eight-Tailed Beast, frequently engaging in friendly conversation with it.
As a Jinchuuriki, Killer B has a massive chakra pool enough to make Samehada get very excited and betray Kisame, who is known for his massive amounts of chakra. Killer B is one of the few people to have achieved full control over a tailed beast and is known as a Perfect Jinchūriki because of this feat, along with Yagura, the Fourth Mizukage, and Naruto Uzumaki.
B is the only known, as well as living, Jinchuuriki who can at will transform and remain in his full tailed beast form indefinitely. 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 Mangekyou Sharingan.