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 Fourth Mizukage was the previous leader in Kirigakure. During his time, the village was known as "Village Hidden in the Blood Mist". Zabuza Momochi once attempted to assassinate the Fourth Mizukage during a coup d'etat but failed. Madara Uchiha could have been the Fourth Mizukage.