Jiraiya (自来也, Jiraiya) 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 fiction book series, called Icha Icha. He was also known as the Toad Sage (蝦蟇仙人, Gama Sennin), because of his signature toad summonings and his status as a Sage.
During the Second Shinobi World War, Jiraiya and his former team-mates fought Hanzō, the leader of Amegakure. Hanzō was so impressed that they could survive in a fight with him, that he bestowed upon them the title of Konoha's "Legendary Three Ninja" (伝説の三忍, Densetsu no Sannin), and that they accept the title in exchange for letting them live. Once the battle was over, Jiraiya and his team-mates encountered three young orphans from Amegakure. While Orochimaru suggested they kill them to spare them the cruelty of the world, Jiraiya decided to look after them for a while and teach them ninjutsu. During the time he spent with them, Jiraiya grew close to the three children, and even wrote a book that was inspired by one of them, Nagato. Eventually, he left them so that they could pursue their own goals. Although news of their exploits reached him from time to time, he thought them to have died during an undisclosed incident.