Yugito Nii

was a kunoichi from Kumogakure. When she was two years old, she became the jinchūriki of the Two-Tailed Monster Cat.

Hidan and Kakuzu arc
She was first seen running through the sewers from some unknown people, who were later revealed to be Hidan and Kakuzu. When she entered a large room, where all the sewers seemed to meet, she finally stopped. After some bickering between the two Akatsuki members, she revealed that she had intentionally led them there, and activated an exploding tag on the tunnel behind them, sealing them in. Knowing that they were from Akatsuki, she transformed into a miniature version of the Two-Tails. However, after a 30-minute unseen battle, she was taken down by Hidan, and brought to the Akatsuki lair. The Two-Tails was extracted from her body, resulting in her death.

During the Five Kage Summit arc, it is indicated that Kumogakure is furious over the loss of Yugito.

Abilities
The only one of her abilities ever shown in the series was the ability to turn into a smaller version of the Two-Tails, giving her an upgrade in her abilities, such as strength and the ability to breathe fire. The way she transformed is very similar to Naruto, being slowly covered in a dense blue chakra that took the form of her tailed beast. It would seem that, although she let go of her control over the Two-Tails, she still had some control over the transformation and how much of its chakra that she would use.

Trivia

 * "Nii" means "second place" in Japanese.
 * Yugito is the only female Jinchūriki, not counting Fū, whose gender is subject to change.