Gengetsu Hōzuki

He was the of Kirigakure.

Background
During his lifetime, he had met Ōnoki when the latter was a kid and had constantly picked on him. He also had an mutual enmity with the Second Tsuchikage, Mū. Eventually both men ended up killing each other during their final confrontation.

Personality
The Second Mizukage is typically laid back, jovial and has a somewhat carefree attitude at times. He is also very charismatic and not averse to praising other people as seen with his unmistakable excitement upon observing the enormity of Gaara's sand attack. In spite of this carefree attitude towards the particulars of his own circumstances, the Second Mizukage still expresses deep concern over the fates of the shinobi originating from his own village, lamenting the prospect of having to confront them after his revival.

He, however, seems to have a short-temper at times, which is especially apparent when concerning Mū and their enmity, which he seemingly places more value upon than even his own life, aptly demonstrated by the manner of his demise and his neglect to ascertain the nature of his resurrection, simply because his killing of Mū was brought into dispute. Part of this enmity seems to be due to the Mizukage's dislike of how selfish and underhanded Mū is.

He also seems to dislike being looked down upon, having intensely reproached Gaara for attempting to take down Mu first before him, seeing this as a tactical approach to take out the stronger opponent, and viewing the Secong Mizukage weaker in comparison to the Tsuchikage.

Appearance
He is an individual of tall and slender stature. His face is accentuated by his relatively long light-coloured hair, worn in a combed back style, a small dark-coloured goatee, a thin moustache and no eyebrows. Due to the effects of the Summoning: Impure World Resurrection technique, he has black sclera and white irides.

His typical attire consists of a long sleeved, high collared robe, which has the pin-striped pattern that is common amongst the shinobi of Kirigakure. This article is worn over a dark-coloured suit, with an equally dark sash wrapped around his waist.

Abilities
As the Mizukage he is an immensely powerful shinobi. He has identified himself as a possessor of Yin Release and thus, also a capable genjutsu user. The fact that he was able to kill Mū, albeit at the cost of his own life also stands as a testament to his skills. Even when informing a considerable portion of the Fourth Division on how to defeat him, none of them were able to grasp the concept behind his techniques, allowing him to kill and injure a significant number with relative ease, suggesting that the Second Mizukage's combat capabilities are truly fearsome.

Nature Transformation
As a member of the Hōzuki clan, the Mizukage can transform his body into a liquid form and back into solid form at will. According to Gaara, the Second Mizukage utilises a type of water that is similar to oil as it was able to seep into his sand and destroy it. When he was restrained by the Binding Tag Seal, the water caused the sand around the seal to darken and then crumble, allowing him to escape. He can also use his right index finger to fire bullets of water strong enough to easily pierce a sand clone.

Summoning Technique
The Mizukage is able to summon a Giant Clam to assist him in combat. By opening its shell and releasing a mist, the creature is capable of producing mirages of both itself and the Mizukage, in order to conceal their true positions. The technique is so baffling that many able shinobi could not figure it out, in spite of the Mizukage explaining it to them.

Shinobi World War Arc
When Mū, despite his camouflage, is detected approaching the Fourth Division, Kabuto Yakushi has Mū summon three other Kage to provide support. Amongst this number is the Second Mizukage, who immediately recognises Mū and the Third Raikage, but fails to identify the other individual summoned alongside him. When told that he has been resurrected, the Second Mizukage is confused by news of his own death until Mū reminds him that they killed each other long ago. This explanation is later confirmed when the Second expresses his desire to kill Mū again but his body wouldn't obey his commands, a clear sign of the control their summoner has over them.

Pursuing the retreating division throughout the entirety of the night alongside the other revived Kage, he laments upon the prospect of confronting shinobi from his own respective village and curses the one responsible for resurrecting them under the belief that this individual is Orochimaru, a remark that meets with the others approval. As the Kage continue to converse, he observes a huge wave of sand bearing down towards them and impressed by the considerable amount, he ecstatically wonders where the shinobi hails from. Saved by the Fourth Kazekage's Gold Dust, the Second Mizukage identifies that he invented an effective counter rather quickly, before being restrained by an arm made of sand during the former's explanation that this technique was used to halt Shukaku when it went on a rampage in the past. Soon after that Mū clashes with Ōnoki, resulting in the formation of an enormous crater in the battlefield and leading the Second Mizukage to recognise the latter as his rival's former bratty disciple, indicating that their deaths occurred long ago.

As the Fourth Kazekage converses with his son about the latter's revival due to the actions of his companions after the extraction of the One-Tail, the Second Mizukage confronts the Kazekage's shock that Gaara possessed friends, asserting that unless the child was really pitiful, it was normal for someone of his age. Upon hearing Gaara's appointment as both Kazekage and Regimental Commander of the Allied Shinobi Forces, he boasts that people without eyebrows were very charismatic, including himself amongst this number. However, this pleasant disposition abruptly changes after learning of Mū's advice to Ōnoki, which indicates that he take full advantage of the situation after the alliance's disbandment to ensure dominance, causing both the Mizukage and Third Raikage to chastise such underhanded tactics. Informing the opposition of their inability to control their bodies, the Mizukage states that they will each reveal their capabilities and weaknesses, in order to quicken their defeat. After the battle commences, he attempts to encircle Gaara while evading his technique but is instead restrained by the embrace of the latter's sand.

Realising that the sand in conjunction with the application of a Binding Tag Seal, would ensure their captivity, he emphatically applauds Gaara's efforts. However, now no longer in control of his body, it reacts instinctively to the threat and instead causes the surrounding sand to crumble, considerably weakening its hold. Freed from his bonds, the Mizukage storms the approaching division alongside the Third Raikage, before divulging the particulars of his abilities. Identifying himself as a possessor of Yin Release and thus a capable genjutsu user, he advises the shinobi to maintain their distance, just as a substantial number are buffeted by his resultant summon.

Phasing through the opposition's attacks without injury, the Mizukage reminds them that it's futile as he was just a mirage and that they should instead eliminate the clam in order to end the technique. Taking his advice into consideration, the shinobi let loose another onslaught but as the smoke clears, they realise that they had once again attacked a mirage. Seemingly irate, the Mizukage tells them to target the clam behind him yet upon trying again, the attack phases through this one as well. Getting nowhere, the shinobi stand in confusion as of how to deal with the situation. As the battle ensues, the majority of the entire Fourth Division faction is incapacitated causing the Second to state that though he did not try to win, he was possibly too strong for his own good with a mixture of both guilt and embarrassment on his face. As Gaara struggles upon his arrival to the battlefield, a visibly disappointed Mizukage, asks if that is all he was capable of. The Mizukage tells him he shouldn't judge someone's strength just by their appearance, Gaara responds that he has learned not to judge someone by their appearance, remembering a previous experience that taught him this lesson.

Gaara restates what the Mizukage said about his genjutsu brought on by the clam, and states that he knows to disperse the genjutsu he needs to destroy the clam. The Mizukage realises in shock that Gaara's sand has been slowly detecting the real clam, and has given Ōnoki the chance to use Dust Release on the clam. The Dust Release fails, which causes the Tsuchikage to resort to using his Earth Release: Fist Rock Technique as a back-up. As he hits the clam, nothing appears to happen, except revealing the clam, but using Earth Release: Super Aggravated Rock Technique, the clam breaks apart revealing the true Mizukage. However, using this technique causes harm to the Tsuchikage's back, leaving him paralysed which gives the Mizukage a chance to mock him before shooting through his body with a bullet of water. Ōnoki's body disperses into sand, which immediately strikes out at the Mizukage, and starts attempting to wrap him up. The Mizukage notices that Gaara's eye of sand had been watching Ōnoki the whole time and wonders if Gaara had switched his sand clone with the Tsuchikage when he was fighting the Giant Clam.

Gaara continues wrapping him with sand, which slowly decays over and over from the Mizukage's oil-water, but eventually upon using Sand Waterfall Layered Imperial Funeral he is able to wrap the Mizukage fully. Then his squad begins to try and seal him, until a large explosion occurs, and the Mizukage's face appears in the sky. When asking what happened, Ōnoki states that it's not a genjutsu but the Mizukage's infinite explosion ninjutsu, Steaming Danger Tyranny.