Mizukage

The is the leader of Kirigakure. As such, their word holds sway over all political and military issues that present themselves regarding Kiri and its inhabitants. Zabuza Momochi once tried to assassinate a Mizukage as part of a coup d'etat, but failed.

Fourth Mizukage
The was a previous leader in Kirigakure. During his time, the village was known as "Village Hidden in the Bloody Mist", the time when the gruesome Academy Student's graduation ceremony of killing one another took place, until Zabuza Momochi slaughtered all the students of one year.