Mito Uzumaki

was a kunoichi from Konohagakure's Senju clan who originated from Uzushiogakure's Uzumaki clan. She was also the first jinchūriki of the Nine-Tailed Demon Fox.

Background
The Uzumaki clan and the Senju clan, being distant relatives, had always had close ties. For this reason, Mito married Hashirama Senju, who would help found Konohagakure and become the village's First Hokage.

During her husband's battle against Madara Uchiha at the Valley of the End, Hashirama at some point gained control of the Nine-Tails. To gain power for Hashirama, Mito used a fūinjutsu to seal the Nine-Tails within herself, becoming the Kyūbi's first jinchūriki. Despite the seal's strength, it almost broke at some later point when she was going through childbirth. Eventually, her husband died in war, and Mito was left a widow.

Towards the final years of Mito's life, it was decided that a new host for the Nine-Tails would need to be found. Kushina Uzumaki, one of Mito's clansmen, was then selected for the role due to her special chakra, and was terrified by the idea. Mito comforted her and, before the transfer was performed, told Kushina that love was the only way to counter the Nine-Tails' hatred.

Appearance
Mito wore an elaborate, high collared kimono with the Uzushiogakure symbol on the back of her obi. Her hair was arranged in buns with hair pin in them and three clips in the front. She also had a diamond mark on her forehead, similar to that of her granddaughter Tsunade. She also wore what appeared to be seal tags in her hair decals. In her old age, she wore a simple loose fitting kimono held closed by a simple obi. She also wore her hair let out with two buns.

Abilities
Not much is known about her fighting skills, but Kushina hailed her as a powerful kunoichi. She was proficient enough with fūinjutsu to seal the Nine-Tails within herself. Also, due to being a member of the Uzumaki clan, Mito had an exceptionally long life. Like Naruto, Mito also had the ability to sense negative emotions due to her control over the Nine-Tails.

Quotes

 * (To Kushina)