Sannin

The Sannin were a group of three legendary ninja, noted to be three of the greatest ninja of their time. While all three eventually left the village at some point for their own reasons, they still retained their title as the Sannin.

History
The Sannin are comprised of the three genin from Team Hiruzen — a genin team led by Hiruzen Sarutobi. When the team was formed, the three genin were only six years old and Hiruzen was already the Third Hokage; they used the bell test to serve as their promotion to genin. When the three shinobi were promoted, as customary, the team disbanded. The three would however work together during the Second Shinobi World War. During their battle with Hanzō of Amegakure, according to Hanzō himself, the three put up a courageous battle against him. Impressed with their power, Hanzō dubbed the three the of Konohagakure. The three would later become legends in the shinobi world, though the Sannin as a team dissolved with Orochimaru's defection from the village.

Every member of this team grew to become Kage-level ninja and with the exception of Jiraiya — who turned down the position — they all became village heads. All of them, at one point or the other ended up leaving the village for various reasons, though Tsunade and Jiraiya would remain loyal to the village. Orochimaru would later join the Akatsuki and after leaving that group, would move on to found Otogakure. Tsunade, after suffering great losses during the Second and Third Shinobi World War, would travel the world alongside her apprentice, Shizune, while Jiraiya would covertly follow Orochimaru's actions and later Akatsuki's, with the goal to protect Konoha from any future external threats. Hiruzen would retire as Hokage, naming Minato Namikaze the Fourth Hokage until the latter's death during the Nine-Tails' attack on Konoha, which forced him to resume office as the Third. He would remain the presiding Hokage until Orochimaru's Invasion of Konoha, which ended in his death. With this, Tsunade took up office as the Fifth Hokage at Jiraiya's — who had declined the position — behest. Three years later, Orochimaru would be permanently sealed by Itachi Uchiha, and Jiraiya would be killed by his former student, Pain, leaving Tsunade as the only surviving Sannin.

Known Missions
Jiraiya, Tsunade and Orochimaru were assigned to locate Hiruko and assassinate him for conducting illegal experiments. This failed, as Hiruko escaped from the village by the time the Sannin reached his lab.
 * Assassinate Hiruko (Movie only)
 * Rank: Unknown
 * Status: Failure

Renown

 * Tsunade, the granddaughter of the First Hokage and grandniece of the Second Hokage, possesses a terribly unlucky addiction to gambling. She became famous during the ninja wars as the world's greatest medical-nin, and she trained Shizune and Sakura Haruno in the art of medical ninjutsu. She later took on the title of Fifth Hokage.
 * Orochimaru, called the prodigy of his generation, defected from Konoha, joined Akatsuki, and founded Otogakure. He sought to gain immortality via means of kinjutsu in order to learn every jutsu in existence. He taught Anko Mitarashi and Sasuke Uchiha, the latter of whom absorbed him. He was later sealed away by Itachi Uchiha.
 * Jiraiya, an eccentric man, 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. He died while investigating Pain but in turn defeated and captured the Animal Path and left invaluable information that led to Pain's ultimate defeat.

Trivia

 * Each member of Team Hiruzen has trained one member of Team Kakashi. Jiraiya has trained Naruto, Tsunade has trained Sakura, and Orochimaru trained Sasuke.
 * The Sannin are all masters of the Summoning Technique and summon using their left hand.
 * On more than one occasion, Team Hiruzen has been shown to wear similar type of clothing, ranging from armoured battle suits to robes with fishnets, a trait not very common amongst other teams.
 * Despite being three of the most powerful shinobi Konoha has ever produced, each of them departed from Konoha for different reasons. Orochimaru left to join Akatsuki and further develop his kinjutsu, Jiraiya went to gather information on Orochimaru, Akatsuki's movements, and find The Child of the Prophecy, and Tsunade lost all confidence in her healing ability and went into self-imposed exile.
 * The Sannin are named after the characters in the Japanese folktale Jiraiya Goketsu Monogatari.
 * The world wide game "scissors, paper, stone" originated from China during the Eastern Han Dynasty (25-220), invented by the warlords of that period. Except instead of paper, they used the open palm symbol to represent cloth, so it's "Scissors, Stone, Cloth". The game reached Japan in the early 1640s and one variation of the game was the "Slug, Snake, Frog" variation. In this variation, the Frog is afraid of the Snake, the Snake is afraid of the Slug, and the Slug is afraid of the Frog. This is influenced by the Sansukumi way of thinking where it keeps the three objects in a deadlock. The fact that the Sannin use these three animals as summons may be the author hinting that there is no stronger one among them, and that their strength is more or less equal.
 * The Sannin once had a friend named Hiruko who later became a missing-nin that appeared in Naruto Shippūden 3: Inheritors of the Will of Fire.