Gamamaru

, more commonly known as the is the oldest and most respected toad of all the inhabitants of Mount Myōboku. Because of his age, the other toads affectionately call him. He is famed for his highly accurate prophecies.

Background
In the anime, over a thousand years ago, Gamamaru laid sight to Kaguya Ōtsutsuki enslaving the land to Infinite Tsukuyomi. Years later, Gamamaru approached the princess' twin sons, Hagoromo and Hamura Ōtsutsuki. He revealed to them the sinister nature of their mother's regular ritual to the God Tree, urging them to seek out the truth. Once the twins learned about the people being offered to the tree, they sought out Gamamaru to hear the whole truth about their mother's actions and the dangers posed by the God Tree, as it was continuously draining Natural Energy from the world, depleting the supply.

Ultimately, the twins asked Gamamaru to teach them senjutsu, which he intended to do from the start. As Hagoromo finished his training in senjutsu, a messenger toad came to inform him and Gamamaru of Hamura's sudden disappearance, speculating that Kaguya discovered their plan. Upon returning the village and evacuating the people for the impending battle, Gamamaru gave Hagoromo a final gift, a sacred seal tag created by the Sage Toads over the centuries that could revive anyone from near death once. From a distance, Gamamaru then watched as Hagoromo confronted Kaguya only to have to fight a brainwashed Hamura. To Gamamura's surprise, Hagoromo chose to fatally wound Hamura to free him from Kaguya's control before using the seal to save him. This impressed Gamamaru, as it also awakened Hagoromo's Mangekyō Sharingan and Rinnegan.

Several years later, Gamamaru gave Hagoromo a prophecy, stating that a "mischievous blue-eyed boy" would unite the tailed beasts and change the world. Years later, Gamamaru approached Hagoromo again after he sent his two sons, Indra and Asura Ōtsutsuki, on separate missions to determine the successor for Ninshū. When noting the two siblings' respective development, he asked Hagoromo what he hoped to gain from this. To which, Hagoromo noted how differently his sons developed, hoping that the journey would help each of them become better balanced by improving where they were found lacking: Indra in compassion and Asura in strength.

As time passed, Gamamaru would often meet with Hagoromo to discuss his plans for his sons. While respecting Hagoromo's request to not interfere, Gamamaru would still watch from afar to see how the two brothers matured.

Centuries later, when Jiraiya was training at Mount Myōboku, the now-elderly Toad Sage made a prophecy concerning him: Firstly, that he would go on to become both a talented ninja, and a pervert without equal. Jiraiya would walk across the world as a sage, "observing all creation, watching as nature takes its course", and in doing so he would also write a book. Jiraiya was also told that he would one day have a student with the power to save or destroy the world, and that it would be Jiraiya's actions that will determine which path this student takes.

Personality
At his great age, Gamamaru seems to constantly smile and tends to have his eyes closed or takes to squinting. He is portrayed and described as being senile, and sometimes out of touch with his present situation, so he does tend to forget things easily and quite quickly. However, when reminded, he is still able to remember things and can easily tell things very precisely. As a sage, he is also very wise, and is quick to stop Shima and Fukasaku from bickering and encourages harmony. It would seem that unlike most other toads, he actually has respect for Jiraiya, and has urged both Shima and Fukasaku to cooperate with him.

Appearance
He is one of the largest inhabitants of Mount Myōboku, easily equalling Bunta, Ken, and Hiro in size. He is brown in colour, with a white belly, is very wrinkled and has taken to squinting. He wears a professor's hat with tassels and an orb on top of it. He also wears a necklace with the toad's village symbol for on it.

The place where he called Jiraiya and Naruto to receive their prophecy is lined with what appears to be giant scrolls and he sits in a shallow pool of water which has the kanji for inscribed on it.

Abilities
Being the oldest toad sage of Mount Myōboku, he is very wise and has immense knowledge and is greatly respected by his fellow toads. Gamamaru is shown to have immense longevity, having been around since at least before the birth of Hagoromo and Hamura Ōtsutsuki.

Senjutsu
Even while he was still very young, Gamamaru had a deep understanding and control of natural energy. By harnessing it, he could easily lift massive stone structures. His knowledge and skill was so great that he played a pivotal role in aiding Hagoromo and Hamura to stop Kaguya, having taught them personally.

Ninjutsu
He could use Water Release to produce a powerful stream of water able to repel a massive bear through solid rock. He can also observe anyone he wants over a great distance as long as he knows the person's chakra pattern using his crystal ball.

Divination
The Great Toad Sage also possesses the ability to see into the future, but to a limited extent, evident by him predicting that Jiraiya would take on a student who would be known as either the Saviour or the Destroyer of the World. He had even bestowed a prophecy to Hagoromo himself, which even to the present day, he still has faith in. Whether this ability is due to his status as a Sage is unknown.

Pain's Assault
Using the Telescope Technique, the Toad Sage watched the meeting between Nagato and Naruto. Jiraiya had originally believed that Nagato was the boy mentioned in the prophecy, but shortly before his death came to believe that Naruto was what the prophecy referred to. When he saw Naruto convince Nagato to sacrifice himself for the citizens of Konoha, the Toad Sage told Gamabunta that both he and Jiraiya were wrong: the prophecy was about Naruto and Nagato. He wonders if The Tale of the Utterly Gutsy Shinobi really was the key to changing the world.

Fourth Shinobi World War: Countdown
When Gerotora asked the Toad Sage if he should give Naruto the key to the Nine-Tails' seal, the Toad Sage had Naruto brought before him so that he could make a prediction. He had foreseen that Naruto would meet a "creature with octopus tentacles" and would battle a "young man with powerful eyes". He also saw that Naruto would be given the key, so he instructed Gerotora to go ahead and give it to him.

Road to Ninja: Naruto the Movie
Gamamaru appears briefly, when a prophecy about the masked man's defeat is made.

Trivia

 * Gamamaru wears a necklace with the kanji character on it. It is frequently used in reference to toads in Naruto.
 * Along with the tailed beasts, Gamamaru is one of the few beings who existed from Hagoromo's era.

Quotes

 * (To Fukasaku and Shima) "No fighting, children. A husband and wife should be nice to each other."
 * (To Gamabunta) "It's over… As it was foretold… but I never thought Jiraiya's two pupils together would be the "Children of the Prophecy", the ones to lead a revolution in the ninja world… Maybe this was all meant to be from the time Jiraiya decided not to give up… That book really was the key to changing the world."