Third Mizukage

The was the leader of Kirigakure.

Background
He accompanied the First Mizukage, Byakuren, to the first ever Five Kage Summit. There he stood behind the First watching diligently as the proceedings unfolded.

Appearance
He was a tall man with black sclerae, no visible pupils, and long, black hair which reached down to his back with what appeared to be pearl-shaped objects encircling his head. He wore the standard Kirigakure attire complete with pinstriped arm and leg-guards over which he wore a sleeveless haori with ragged ends and a poncho-like scarf around his neck. At the time of his death, he had aged considerably, with notable creases, visible frown lines around his mouth, and much lighter-coloured hair.

Abilities
Though the Third Mizukage's abilities remain mostly unknown, the fact that he was chosen as the Kage of his village, suggests that he was the most powerful shinobi of Kirigakure in his time, as the village chooses only the strongest warrior as its leader. Even before becoming the Mizukage, his power was such that he was chosen to be the bodyguard of the First Mizukage.

Kaguya Ōtsutsuki Strikes
Subsequent to Kaguya Ōtsutsuki being sealed by Naruto Uzumaki and Sasuke Uchiha, he and the other deceased Kage were summoned from the Pure Land by Hagoromo Ōtsutsuki to aid him and the Hokage in summoning Team 7, the tailed beasts, and Madara Uchiha from Kaguya's dimension. Later, his and the other Kage's souls were returned to the Pure Land.

Trivia

 * He was the only bodyguard of the first Kages during the First Five Kage Summit that didn't become the Second Kage of his village, although he did eventually become the Third.