The world of Naruto features a robust cast of lovable characters set in a world based on Japanese myth, and some take more inspiration from those myths than most westerners would recognize. The series' most powerful ninja trio, the legendary Sannin, have cemented their place in the hearts of fans. What they might not know, is that these characters existed long before the series did.
Jiraiya, Tsunade, and Orochimaru make up the Sannin in the ninja world, and their abilities are based on toads, slugs, and snakes, respectively. They start as childhood friends, growing up in wartime. As they grow older, conflict arises between them, and they go their separate ways. Each one is immensely powerful and proves pivotal to the series' plot with Jiraiya's death in Naruto: Shippuden being a major turning point for the series. There is something undeniably tragic about it as Jiraiya dies, Orochimaru is evil, and Tsunade loses many of those close to her. Though all three have their roles to play in the world of Naruto, it's Jiraiya who is the main focus of the trio's mythological basis.
The Tale of Jiraiya the Gallant was published in Japan from 1839 to 1868 and collects 43 illustrated novels. Just like Naruto, it was incredibly popular and adapted into various different media. As with most tales of old, there are several different versions, but the main points can be summarized as Jiraiya, Tsunade, and Orochimaru learn toad, slug, and snake shape-shifting magic. After being possessed by a snake demon, Orochimaru becomes power-hungry and wants to take over Japan. Jiraiya tries to stop him but is defeated, so he searches for and enlists the help of Tsunade. Together, they are able to exorcise the snake demon from Orochimaru and save Japan.
Since this story was widely known and ired in Japan, it makes sense that creator Masashi Kishimoto wanted to include it in his ninja universe. The story boasts impressive artwork in the traditional Japanese art style, Nihonga, although it seems that Kishimoto went with his own ideas for the character's designs. It is based on the three-way-deadlock, which is the same idea as "Rock-Paper-Scissors": snake beats toad, toad beats slug, slug beats snake. Naruto itself loosely adapts this idea in the climactic battle of the "Finding Tsunade" arc, which not only shows the Sannin together for the first time in the series, but also demonstrates the awesome power that gives them that name.
Kishimoto did a fine job of continuing their stories and adapting their shapeshifting powers into his own system of chakra and ninjutsu, which pays off when the main protagonists use them during the series' final battle. It's no wonder that fans have come to love the powerful trio. The legend of Jiraiya, Tsunade, and Orochimaru might have been well known in Japan long before the series existed, but there's no doubt that Naruto helped them gain worldwide popularity.
