Byakuren in Naruto

Byakuren was Mizukage, who attended the first-ever meeting of all five Kage. He was suspicious of Hashirama Senju because he was too humble with them. But then when Reto asked for a 30% cut from their purchase of Tailed Beast, he got furious and asserted that other nations could join together to destroy Reto and his nation. However, Hashirama told everyone to stay together.

After Naruto Uzumaki and Sasuke Uchiha sealed Kaguya Otsutsuki, Hagoromo Otsutsuki summoned the deceased Kage, including Byakuren. He did that to help him and the Hokage in summoning Team 7, the tailed beasts, and Madara Uchiha from Kaguya's dimension. Eventually, Byakuren and the other Kage's souls were sent back to the Pure Land.

Byakuren was a bit impatient and had a short temper, as seen in the anime. He was not trustworthy with others, as he said in the meeting when Hashirama was humble with them.

Byakuren, in his old age, had long, grey hair that covered much of his face, along with a long mustache and beard that merged into one. He had a scar across his left eye, which was blind, while his right eye was black. His teeth were sharp and triangular, like those of other Kirigakure shinobi. He typically wore a loose-fitting, light-colored kimono over dark pants.

Byakuren abilities were not seen in the anime, but he was the founder of Kirigakure and the Mizukage, which means he must be very powerful.