The Legendary Sannin

Jiraiya (自来也) was one of the legendary Sannin, along with Tsunade and Orochimaru, who was trained by the Third Hokage. He was a self-proclaimed super-pervert, and wrote a popular adult book series called Icha Icha, a favorite of Kakashi Hatake. He was also known as the Toad Sage (蝦蟇仙人, Gama Sennin), because of his signature toad summonings. He was the Fourth Hokage's teacher. He then became Naruto Uzumaki's teacher. Jiraiya had the kanji for "oil" on his forehead protector.

Orochimaru (大蛇丸, Orochimaru) was one of Konohagakure's Sannin. He later became a member of Akatsuki and the leader of Otogakure. He was the primary antagonist for most of Part I.

Tsunade (綱手) is the Fifth Hokage (五代目火影, Godaime Hokage) of Konohagakure, taking over after Hiruzen Sarutobi died. Along with Orochimaru and Jiraiya, she is one of the Legendary Sannin of Konoha, and the only one left alive after Jiraiya's death and Orochimaru's permanent sealing. She excels in medical ninjutsu.