Mujō

is the master of Hōzuki Castle.

Personality
Despite his job as master of a prison, Mujō believes rehabilitation is possible for even the worst criminals. He also a selfless man; despite Kusagakure being uninterested in aiding other villages in matters that had no affect on them, Mujō offered Konohagakure some aid in coordinating a mission to protect the potential informant. He also does not tolerate any of his subordinates who abuse their authorities, as he swiftly fired Benga upon discovering his of soliciting bribes from inmates and extending sentences for his own reasons. He appears to have a heart condition, requiring medicine to be on him at all times.

Appearance
Mujō is a tall and lean middle-aged man of pale complexion. He has a full head of grey hair with bangs hanging over left eye and also sports a full but well-groomed beard with a mancho moustache. He has heavy tear-lines under his eyes and pronounced cheekbones. He wore some sort of suit with a brown belt and a silver buckle. He also wore brown boots.

Abilities
Mujō utilises his clan's hiden Fire Release. Combining it with Juinjutsu, he can brand people, blocking off their ability to mould chakra and even more, prevent the target from leaving a certain radius without bursting into flames. In addition this technique being the focus point of keeping prisoners on lockdown in Hōzuki Castle, he's skilled enough to fake an application of this technique in front of other prison employees without them suspecting anything. Also, as the warden of the Hōzuki Castle, he had access to its summon: a two-headed, fire-breathing hound passed down from warden to warden, used to hunt down prisoners who attempt to escape.

Mujina Bandits Arc
When Boruto Uzumaki and Mitsuki were sent to prison as wanted criminals, Mujō was first to greet all the new inmates, explaining the nature of their imprisonment and branded them all with his technique before leaving and letting Benga take over the explanation. Secretly, Mujō was working in league with Konohagakure.

Having learned that one of Hōzuki Castle's prisoner was a deserter of the infamous and elusive Mujina Bandits, Kokuri, who was willing to give information on the gang in exchange for protection from them, Naruto Uzumaki reached out to his old acquaintance in Mujō for help. With the warden's influence, they were able to smuggle Boruto and Mitsuki with false identities while applying a fake brand on the two genin so they could still use their chakra. When Sarada Uchiha infiltrated the prison as a journalist student researching the prison, Mujō talked to her and regretted not being able to offer more support to their mission.

After Kokuri was mysteriously attacked by a prisoner, Sarada requested that Mujō transfer Kokuri to Boruto and Mitsuki's cell for protection. However, while Mujō agreed to help, his position in the castle was more a figurehead than actual authority, as Benga, the chief officer, had final say and declined the request. Realising they needed to pressure Benga somehow, they learned that Benga was secretly taking various bribes from the prisoners for special requests. Sarada found a journal of his dealings and presented it to Mujō. Using this leverage, Mujō had the authority to take full command of the prison, successfully moving Kokuri to Boruto and Mitsuki's cell.

Later, Mujō received confirmation from Kusagakure that Kokuri would be released on parole. He also learned of Benga having repeatedly abused his authority to extend prisoners' sentence. Deciding Benga was too amoral to have any authority, Mujō fired him. However, before he could inform anyone of this, his heart condition acted up. Seeing this as his chance to save his position and take full authority of the prison, Benga swiped Mujō's medicine out of his grasp, watching smugly as Mujō collapsed and was rushed to the medical wing.

Later, Mujō made a full recovery and, following Benga's death, was restored to his position at Hōzuki Castle, which allowed him to retract Benga's unlawful sentence extensions.

Trivia

 * Mujō's name means "uncertainty", "transience", "impermanence", or "mutability".