Utakata

was a shinobi from Kirigakure and the jinchūriki of the Six-Tailed Slug. The Six-Tails has been captured and sealed by Akatsuki, causing Utakata's death when the beast was extracted. While the events surrounding his capture and death are currently unknown, Utakata and the Six-Tailed Slug have appeared in a filler arc in the anime even though they are actual streamline characters.

Personality
Kishimoto described Utakata as "charming". Utakata is usually depicted with a stoic, emotionless look. The only time he has shown emotion at all, anger, was from his desire not be called, saying he is not foolish enough to be titled "master". Utakata is a loner who shows no emotional attachment, yet has a strong sense of honor, determined to repay his debts to others.

Appearance
Utakata is a tall, thin young male with dark brown, shoulder-length hair with amber-colored eyes. He wears a long blue kimono with an orange sash belt. He carries a bamboo jug which is filled with a soap solution inside his kimono that's tied on by his orange sash. His kimono sports a small crest near the back of his neck that appears to be a simplified image of three bubbles.

Six-Tailed Beast arc
In the anime, Utakata became a wanderer, constantly fighting off people going after him. One day, he was attacked again in front of a girl named Hotaru. While defeating his attackers, he was injured. Believing that Utakata saved her, Hotaru took him to her family's fort for treatment. After recovering, Utakata was begged by Hotaru to train her in his ninjutsu, to which he refused, not wanting to become anyone's master. Wishing to repay his debt having his life saved, Utakata agreed to make sure Hotaru and her grandfather's secret jutsu would safely be delivered to her clan's village. Along the way, he met Naruto Uzumaki and his team who were also assigned to protect Hotaru. Seeing that the Leaf ninja were strong, he felt he could trust them alone to guard her, freeing him from his debt and left, despite Hotaru's pleas for him to stay.

Abilities
Utakata fights using ninjutsu from the  of ninjutsu, using a unique kind of bubble-blowing relic. In the anime, it is shown he is able to stand inside the bubbles he blows and can float along inside them. He can also trap his enemies in his bubbles and kill them with his technique, Ink Bubble Explosion. He is also shown to be highly evasive, effortlessly dodging all of Naruto's attacks.

Trivia

 * refers to bubbles on the surface of a liquid. Idiomatically, it also means "transient," "ephemeral."
 * In the anime, Utakata and the Six-Tails remain yet to be captured by Akatsuki. In order to avoid conflict with the manga, it seems inevitable that, by the end of the arc, Utakata will have been captured and the Six-Tails extracted, resulting in his previously-unseen death, in a manner similar to the Three-Tailed Giant Turtle.