Kahyō

is the warden of Hōzuki Castle, formerly a missing-nin and a bodyguard of the Ryūha Armament Alliance's leader, Garyō

Background
At some point in time, Kahyō and her son, Hakuhyō, left Kirigakure and settled in the Land of Waves, in the hopes that he would not be persecuted by the village.

Appearance
Kahyō has long, curly hair. Her shinobi-attire consists of snow-white clothes and a mask with a hook-pattern on it. In disguise, she wore a long, blue dress.

Abilities
Kahyō has shown to be a very skilled kunoichi being able to go head to head with Kakashi Hatake, the Sixth Hokage, and surprising him on several occasions. Her power was also enough to defeat the Fourth Raikage in a training bout. As further testament of her skills, Kakashi recommended that she be put in charge of the Hōzuki Castle.

Nature Transformation
Kahyō is able to utilise the Ice Release, by simultaneously combining the water and wind-natured chakra to produce ice. Through the use of her kekkei genkai, Kahyō can freeze moisture in the air to form ice swords, which she can form from great distances. She is also able to freeze targets to death by causing ice particles to form on their body either remotely or through physical contact. The technique is very useful in neutralising shinobi and is on par with the Fire Release: Heavenly Prison.

Kakashi Hiden: Lightning in the Icy Sky
After failing in her mission but seeing the error of her decisions, she agreed to repent by taking up for life the position of running the Hōzuki Castle. Four months after taking the post, she writes a letter to Kakashi telling him that things have been busy.

Trivia

 * Kahyō is mentioned in Naruto Shippūden: Ultimate Ninja Storm 4 in a side quest in the Shikamaru's Tale Adventure Mode DLC. It is revealed that shortly after she took over as lord of Hōzuki Castle, the number of secondary offences within the prison had dropped significantly. As a result, Shikamaru suggests that Kakashi send her a gift to reward her for all her hard work.
 * Despite being Ice Release users, is it unknown whether Kahyō and her relatives are from the Yuki Clan.