Mui

is a primary antagonist that appears Naruto 5: Blood Prison. He is the of the prison castle Hōzukijō, and a jōnin-level shinobi from Kusagakure.

Appearance
Mui has long black hair that goes beyond his shoulders. He wears some sort of suit with a brown belt and a silver buckle. He also wears goldish-brown boots.

Abilities
Mui has shown great skill with taijutsu, able to defeat multiple prisoners barehanded without losing his composure, as well as easily defeat a weakened Naruto with a series of swift punches. Even after suffering a mortal wound through his chest by his son, Mui managed to get back up on his feet and apply a powerful seal.

Nature Transformation
Mui has demonstrated great proficiency with Fire Release. The most prominent of his fire techniques is one which can bind a prisoner and prevent them from moulding chakra while at the same time absorbs their chakra after he applies a formula to them, it will also set them aflame should they try to escape. He also has an advanced form of this which he can use on larger targets. By altering this technique, he can surround his arm with fire to use as a blade which can use to engulf those he stabs in fire.

Trivia

 * His name means "inactivity".