Hair color: white (in manga), blond (in anime)
Classification: Jinchuuriki of the Hachibi
Affiliation: Kumogakure
Killer B is a powerfully built shinobi from the Hidden Cloud Village and one of the few perfect jinchuuriki—meaning he's achieved complete control over his tailed beast, the Eight-Tails. He apparently comes from the Yotsuki clan and has a pretty distinctive look: white hair in the manga (blond in the anime), an "iron" tattoo on his right shoulder, and a bull's horn tattoo on his left cheek that mirrors one of his beast's missing horns. He's also known for carrying seven swords into battle.
His bond with the Eight-Tails is unusually strong and genuinely friendly—they actually have conversations and work together seamlessly in combat. This gives him an enormous chakra pool that even made the legendary sword Samehada betray its previous wielder just from the sheer amount of energy B was putting out.
B earned his name as a kid when he was the only child able to pull off a Double Lariat maneuver with A, the future Raikage. A declared them brothers from that moment on. At five years old, after the previous Eight-Tails jinchuuriki lost control and killed several ninja, B was selected to become the new host.
He's got a pretty particular personality—demands to be called "Lord Jinchuuriki" and insists his beast be addressed as "Lord Eight-Tails." He also has this habit of busting into rap mid-conversation, even during fights, sometimes stopping combat entirely to work on rhymes. He apparently dislikes bright light and doesn't seem too bothered by most things, staying casual even when things get serious.
During the Third Great Shinobi War, he and A crossed paths with Minato Namikaze and had a brief skirmish. What really sets B apart is that he's the only known living jinchuuriki who can fully transform into his tailed beast form at will and stay that way indefinitely, something only a handful of others have ever managed.
Content compiled by AnimeList.moe from publicly available sources.