Matatabi

Shaped like a folklore nekomata, this giant cat carries two tails and burns head to foot in flame, though its fire glows an animated cobalt and black rather than ordinary orange. No pupils mark its mismatched eyes, the right a shade of yellow and the left green, as with an odd-eyed cat. Tobi's forced transformation swelled it well past the scale Yugito had drawn out on her own. Back in the Sage's twilight days it was merely a small burning kitten, and yet it already dwarfed the man who created it.

A tailed beast's endless chakra is Matatabi's to share with allies, and its healing knits wounds, its own and others', in mere seconds. Death barely holds it, for a slain Matatabi returns in a more youthful shape. It shapes the Tailed Beast Ball, and pliant muscles give the creature speed and reflexes at odds with its bulk. One paw swipe can pulp or hurl a foe, and its tails, joined with those of the other beasts, once broke apart a complete senjutsu-charged Susanoo. True to the flames it wears, the cat wields Fire Release and hurls fireballs.

Matatabi was born in Hagoromo Otsutsuki's last years, when the Sage divided the Ten-Tails' chakra among nine named creatures. He warned the young beasts that a tie still joined them all, promising a distant reunion and a person who would teach them true strength. The anime adds that he hid the cat inside a temple set in a canebrake, and rumor later held that, much like Shukaku, it began as a human turned living ghost. Generations past Konoha's birth, Hashirama Senju handed the beast and Gyuki over to Kumogakure during the Five Kage Summit to steady the balance of power, a truce that shattered once the First Shinobi World War began. At two years old Yugito Nii became its host and trained brutally to master it. Come the Fourth Shinobi World War she fell to Akatsuki, and over three days the pair's extraction sealed the Two-Tails away in the Outer Path's demonic statue, which killed her.

Reborn and wrenched into full form by Tobi, the cat fought the Allied ranks until a transformed Naruto drove it back. Meeting him deep in the beasts' shared mind, it named itself, vowed to keep its promise to Son Goku, and once freed confirmed that Naruto was the child the Sage had foretold. It later tore loose from Obito, struck at Madara before being chained anew, and lent its power against Kaguya, and after Sasuke's brief imprisonment of the beasts it went free once more. In the later era it, alongside Kokuo and Chomei, refused human help against Urashiki, still fearing capture despite trusting Naruto.