The students of Hiruzen Sarutobi, members of his Team Hiruzen: Jiraiya, Orochimaru, and Tsunade. They possess exemplary ninja abilities. When they were young and relatively unknown during the Second Great Shinobi World War they fought against Hanzō, and for being able to survive his attacks he gave them the title of Konoha's Sannin in return for letting them live. After that, their names became famous throughout the world.
The Sannin are widely regarded for their great skill and power, each one has the level of being a Kage in their own right; each has been considered for the position of Hokage at different points in time, with one of them obtaining the title. When Orochimaru defected from Konoha after being denied the position, the Sannin were disbanded, though they continued to be known by the title.
Tsunade, the "Slug Princess," granddaughter of the First Hokage and grandniece of the Second Hokage. Possesses a terribly unlucky addiction to gambling. Became famous during the ninja wars as the world's greatest medical-nin. Trained Shizune and Sakura Haruno in the art of medical ninjutsu. Took on the title of Fifth Hokage.
Orochimaru, the "White Snake," defected from Konoha, joined Akatsuki, and founded Otogakure. Sought to gain immortality via means of kinjutsu in order to learn every jutsu in existence. Later he taught Anko Mitarashi and Sasuke Uchiha, the latter who absorbed him, and later sealed away by Itachi Uchiha.
Jiraiya, the "Toad Sage," wandered the world, discovered and trained under the toads and wrote "The Tale of the Utterly Gutsy Shinobi" and the Icha Icha series of novels. Later he became the teacher of Yahiko, Konan, Nagato, Minato Namikaze, and Naruto Uzumaki. Died while investigating Pain but in turn defeated and captured the Animal Path in the process.