Mizukage

The is the leader of Kirigakure. As the official head shinobi of the Hidden Mist Village, his word holds sway over all political and militaristic issues that present themselves regarding Kirigakure and its villagers.

First Mizukage

 * Age: Unknown (Deceased)
 * Rank: Mizukage
 * Height: Unknown
 * Weight: Unknown
 * Birthday: Unknown
 * Blood Type: Unknown

The First Mizukage was probably the founder or one of the founders of Kirigakure.

Second Mizukage

 * Age: Unknown (Deceased)
 * Rank: Mizukage
 * Height: Unknown
 * Weight: Unknown
 * Birthday: Unknown
 * Blood Type: Unknown

Nothing is known about this Mizukage, except that he was the village leader after the First Mizukage.

Third Mizukage

 * Name Madara Uchiha
 * Age: Unknown
 * Rank: Mizukage
 * Height: Unknown
 * Weight: Unknown
 * Birthday: October 19
 * Blood Type: Unknown

The Third Mizukage was the village leader when the Kaguya clan attacked Kirigakure. When a group of sword-using shinobi slaughtered the entire clan (except for Kimimaro), the Third was so impressed that he named this group the Seven Swordsmen of the Mist. The Third Mizukage would later be revealed as Madara Uchiha and lets Kisame Hoshigaki (one of the ninjas he named Seven Swordsmen of the Mist) know that he's counting on him.

Fourth Mizukage

 * Name Unknown
 * Age: Unknown
 * Rank: Mizukage
 * Height: Unknown
 * Weight: Unknown
 * Birthday: Unknown
 * Blood Type: Unknown

The Fourth Mizukage became corrupt with power and ran the village with an iron fist disbanding the Seven Swordsmen and creating their own personal guard to protect them rather then to stick with old tradition. This corruption and abuse of power were said to have been present all the way into recent times. It is possible that these events are what lead up to Zabuza Momochi, being the former, albeit most recent leader of the Seven Swordsmen and former ANBU squad captain, leading the failed assassination attempt on the current Mizukage. This is all but speculation.