Gamamaru

The is the oldest and most respected toad of all the inhabitants of Myōbokuzan. Because of his age, the other toads affectionately call him.

Personality
Being several thousand years old, he is the oldest and most respected among the populus of Myōbokuzan. At his great age, the Great Toad Sage seems to constantly smile and tends to have his eyes closed or 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.

Jiraiya Ninja Chroncles Arc
During Jiraiya's fight with Pain, he has a flashback to his encounter with the Great Toad Sage. Famed for his highly accurate prophecies, the Toad Sage makes one concerning Jiraiya: Firstly, that he would go on to become both a talented ninja, and a pervert without equal. Furthermore, 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. Jiraiya had initially assumed Nagato to be the student of the prophecy, but before he is killed, Jiraiya realizes that it was Naruto all along.

Invasion of Pain arc
After Naruto finally wins the fight against Pain and gains the trust of Nagato who then uses his the rest of his powers, in turn sacrificing himself, in order to revive the people he killed during the invasion it is revealed that the Great Toad Sage has seen it all using the Telescope Technique. He is seen sitting together with Gamabunta who is wrapped up in bandages on his entire upper body and arms. When the Great Toad Sage tells that it was over Gamabunta asks what was going on and the Great Toad Sage replies that it happened as it was foretold. Though he mentions he didn't expect that it was two of Jiraiya's pupils who were the children of prophecy and would bring about the revolution of the ninja world. He then states that maybe it was all meant to be once Jiraiya decided never to give up and the first book he wrote really was the key to changing the world.

Fourth World War arc
He sent Fukasaku to summon Naruto and when he got to Myōbokuzan, he told Naruto his future. He tells him that he is going to meet an an octopus with tentacles and battle a  young man with great power in his eyes.

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 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."

Trivia

 * The Great Toad Sage wears a necklace with the kanji character on it.  This same character was first seen in the series on Jiraiya's customized Forehead Protector.  This kanji character, meaning, is seen as serving as a symbol for the Ninja-Toads of Myōbokuzan, a possible allusion for the Toad's signature technique, the Toad Oil Bullet technique.