Otogakure

, called Oto for short, was Orochimaru's personal village, founded for the express purpose of collecting ninja for his experiments and quest to learn jutsu. In actuality, Oto is not really a village but a group of hideouts and bases scattered through out the Land of Sound and other countries. Three Sound ninja (Dosu Kinuta, Zaku Abumi, and Kin Tsuchi), under Orochimaru's orders, entered the Chunin Exam with the goal of killing Sasuke Uchiha. However, Orochimaru was actually using them as test subjects for Sasuke's power after Orochimaru gave him the cursed seal. Sound ninja use a diverse amount of jutsu. The Oto symbol is an eighth note.

Trivia

 * Despite not being one of the five great villages, Orochimaru has been dubbed by fans as "Otokage", due to his powers being that to rival a Kage-level ninja.