Yagura was the jinchūriki of the Three-Tails and the Fourth Mizukage, Yondaime Mizukage; Literally meaning "Fourth Water Shadow") of Kirigakure. When the Three-Tails was captured by Akatsuki, it had no host and roamed out in the wild. However, upon his resurrection, the Three-Tails appears to have been resealed within Yagura.
Abilities
Not much is known about his abilities except that he was presumed to be a powerful shinobi, due to him being chosen as the Mizukage. He wields what resembles a large, hook-ended staff with one end being larger than the other. A green flower is also located on the larger end. By incorporating this tool into his Water Release ninjutsu, Yagura is able to create mirrors that can reflect enemy attacks.
During his time as Mizukage, the village was known as the "Village of the Bloody Mist", mostly because of the barbaric ritual where Academy students kill one another in order to graduate. This practice was discontinued when an entire graduating batch of Academy students were massacred by a young Zabuza Momochi. It is likely that Yagura was the Mizukage whom Zabuza tried to assassinate when he revolted.
Yagura was also known to dispatch Kiri-nin who were suspected of being disloyal to the village immediately (commending and taking Kisame Hoshigaki as his direct subordinate after assassinating Fuguki Suikazan, a traitorous member of the Seven Ninja Swordsmen of the Mist). Yet despite the terror of his reign, he appeared to be kind. Apparently the people of Kiri feared that Yagura was being manipulated, a fear which was confirmed by Ao, who saw through an unnamed genjutsu with his Byakugan, later identified by Kisame as the work of Tobi.

