Gengetsu Hōzuki

He was the of Kirigakure.

Background
During his lifetime he seemingly had a significant and mutual rivalry with the Second Tsuchikage, Mū. Eventually, this contestant relationship would lead both men to their deaths, as they each successfully manage to kill each other during a confrontation.

Appearance
The Second Mizukage is an individual with a fairly tall and slender stature in comparison to others. His elongated face is accentuated by his relatively long light-colored hair, worn in a combed back style, and the presence of a small dark-colored goatee and thin moustache. Due to the effects of the Summoning: Impure World Resurrection technique, he has black sclera and white irides.

His typical attire consists of an extremely long sleeved and high collared light-coloured jacket, which descends to below his knees and displays the prominent pin-striped patterning that is common amongst the shinobi of Kirigakure. This article is worn over a dark-colored and high necked suit, with an equally dark sash wrapped around its exterior at his waist.

Abilities
Although he has yet to be observed in combat, the simple fact that he was able to kill Mū, albeit at the cost of his own life, stands as an appropriate testament to his proficient skills. This is because even some of the most notable shinobi of the Allied Shinobi Forces greatly feared that no one but Ōnoki, a former pupil and possessor of the same kekkei tōta as Mū, would be able to stop the former Tsuchikage, suggesting that the Second Mizukage's combat capabilities are truly fearsome.

Shinobi World War Arc
Mū, as a former Kage, is resurrected alongside various other notable shinobi by Kabuto Yakushi, in preparation for the Fourth Great Shinobi War. He, the Third Raikage, and the Fourth Kazekage are sent to provide backup for the Second Tsuchikage in fighting the Fourth Division. Although he wants to try and kill the Tsuchikage again, he is forced to join the others in battle.