Sakon and Ukon

As conjoined twins, both Sakon and Ukon had fair-skin and straight, dark blue hair (in the anime, it has a more of a light blue-grey colour) with long bangs that covered each different eye, their bangs were on opposite sides (Ukon's being on the left, Sakon's on the right). They both wore a green shade of lipstick, and had dark markings around their eyes, giving them an androgynous appearance. In most appearances, Sakon is usually shown with a smirk on his face and his head slightly tilted down. As Ukon usually slept inside Sakon's body, his head would protruded the back of Sakon's upper back and hanged limply, making his hair cover his face. Both of the twins have a cursed seal planted on their foreheads just above their eye, which are covered by their bangs. The twins' attire was a black shirt under brown tunics with long sleeves and bore the symbol of the Sound Four on the hem, and black skin-tight shorts. They wore black arm-warmers (which are mistaken for being part of their sleeves), traditional black shinobi sandals with calf-length leg warmers covered by bandages, and a purple, rope-like belt tied in an inverted bow around their waists. To help distinguish between the two, Sakon wore a dark-red beaded necklace around his neck and carried a giant scroll behind his back through one of the loop of his rope-like belt, while Ukon lacks any embellishments in his uniform and had a somewhat deeper voice than his brother. After being reincarnated, Sakon and Ukon looked like they did while alive with the exception the grey sclerae common in all the other ninja Kabuto Yakushi brought back.

In the anime, the Sound Four were originally prisoners of Orochimaru, forced to fight other prisoners to the death in battle royales. By surviving their respective matches, they proved themselves to be the strongest of Orochimaru's prisoners and as such were made his bodyguards. The Sound Four were at some point forced to accept Kimimaro as their leader, who easily defeated them all in battle and, because of his Shikotsumyaku abilities, was slated to be Orochimaru's next host body. Under Kimimaro their group was known as the Sound Five (音隠れの忍五人衆, Otogakure no Shinobi Gonin Shū, literally meaning: Hidden Sound Shinobi Five People). In the anime, the Sound Five assisted Orochimaru with assassinating the Fourth Kazekage and killing Shiore's team during the Chūnin Exams in Konohagakure. Kimimaro fell terminally ill after this, forcing him to withdraw from the group; he became ill at some unspecified time in the manga.