The Mizukage (水影, Literally meaning: Water Shadow) is the leader of Kirigakure. There have been five official Mizukage, though only three have been seen in the series thus far. Their word holds sway over all political and military issues that present themselves regarding Kirigakure and its inhabitants. The Mizukage's building is the widest and largest landmark in Kirigakure, bearing the kanji for Mizu (水, Literally meaning: Water) on it.
List of Mizukage
Main article: Yagura Yagura (やぐら, Yagura) was the jinchūriki of the Three-Tails and the Fourth Mizukage (四代目水影, 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. He was controlled by Tobi who could be called the "real" Fourth Mizukage.
Main article: Mei Terumī Mei Terumī (照美メイ, Terumī Mei) is the Fifth Mizukage (五代目水影, Godaime Mizukage, Literally meaning: Fifth Water Shadow) of Kirigakure. She became Mizukage after the dreadful reign of Yagura ended, and has worked tirelessly to reform internal policies and recreate diplomatic relations with other villages.