Mui

Mui lets his black hair fall well below the shoulders, though a decade back it hung only to about shoulder length. Day to day he dresses in a tailored suit belted in brown with a silver buckle, and brown boots. In the company of the Fruit Group he conceals himself under loose black robes and a bull's metal head.

Stern and humourless, Mui obeys his own rules to the letter and lets little through his guard beyond anger, meting out savage punishments to inmates who defy him. When he handed Muku over to the box without a flicker of grief, Ryuzetsu and the four councillors judged him a heartless man ready to sacrifice anyone for Kusagakure. In fact the opposite holds: he would give up the village before his son, and the hope of Muku's return cracks him open into weeping. Older recollections reveal a warmer man who treasured both wife and child.

Widowed just after Muku came into the world, Mui brought the boy up alone and adored him, ramen trips included. Charged with guarding the Box of Ultimate Bliss, he once attempted to pry it open with Muku's chakra, hoping to wish Kusagakure back to its former glory; the child's reserves came up short and the box devoured him instead. Consumed by grief, Mui hunted in secret for a means to reopen it and reclaim his son. Warden and jonin alike, he was a fearsome fighter, felling prisoners and a drained Naruto with bare knuckles and pressure-point blows, and hardy enough to rise again after a mortal chest wound to set one final seal. His true gift was Fire Release, sheathing an arm in flame to serve as a sword and, above all, a technique threaded with cursed sealing that locked a target's chakra, drained it, and set the victim ablaze if they strayed too far.

Mui debuts by laying out the castle's rules to a fresh batch of prisoners and searing Naruto with that sealing flame, brushing off the boy's protests of innocence. After a clone ruse and a scuffle, the real Naruto is drained of chakra to feed the box, which finally stirs to life. The Fruit Group expects a wish to restore the village, only to hear Mui beg through tears for his son's return. Muku steps out, drives a hand clean through his father's chest, and turns into the demon Satori. Spurred by Naruto's words, Mui hauls himself upright and clamps the creature down with his Great Fire Heavenly Prison long enough for Muku to surface; a final blow from his son then hurls his body across the hall into the memorial he had raised for his late wife, and there he dies. Left without a warden, Hozuki Castle eventually passed to Kahyo once the Fourth Shinobi World War had ended.