The Eight-Tails
The Eight-Tails ended up sealed in Killer B after his relatives—his cousin, cousin's uncle, and cousin's father—all failed to control it before him.
B is one of the rare jinchūriki who actually got the upper hand with his beast, and it shows. Unlike the Nine-Tailed Demon Fox, which constantly threatens its host and needs to be locked down just to have a conversation, B and the Eight-Tails have a genuinely relaxed dynamic. B will literally sit on its nose while they chat. That said, B annoys the thing constantly; his goofy personality clashes with the beast's serious nature, which only winds it up more. The Eight-Tails doesn't hold back trash-talking him because of it. It'll even call him out in real situations—like when it scolded him for rapping during his fight with Kisame instead of staying focused. The beast clearly takes responsibility way more seriously than B does.
Before B learned to manage it, the Eight-Tails was notoriously vicious and uncontrollable, going on brutal rampages whenever its previous hosts lost their grip.
Despite their solid relationship, the Eight-Tails' core drive remains self-preservation like any other tailed beast. When cornered by Kisame, it was ready to fight back even with Sabu and Ponta nearby. Still, it showed real smarts by telling B exactly how to lure Kisame away without putting his friends in danger. The beast has admitted it used to be way more aggressive but that B changed it. More surprisingly, it actually helped push B into assisting Naruto gain control of the Nine-Tails—even though it doesn't like that beast—suggesting it's got some genuine compassion underneath the irritability. Both B and the Eight-Tails have warmed up to Naruto since then.
The Eight-Tails also isn't shy about disciplining B, usually played for laughs. It once headbutted him when he started perving out about Yugito's chakra points placement.
Among the other tailed beasts, the Eight-Tails has made clear they're all individuals with real emotions and personalities. It resents how the Nine-Tails ranks them purely by tail count and gets genuinely angry watching other beasts get forced into servitude.
Content compiled by AnimeList.moe from publicly available sources.
