In the Sound Shadow's office in Otogakure, in the Land of Rice Fields, Madara Uchiha had received all of Orochimaru's research on Jūgo.
Clearly, Orochimaru had put considerable effort into studying Jūgo's body. He had even developed a Cursed Seal that could help ninja absorb nature energy.
According to Orochimaru's information, Jiraiya might also have some knowledge of Nature Energy. Ryūchi Cave, the home of Orochimaru's summons, even offered instruction in it. Anyone who mastered it could gain Sage Power.
After receiving Orochimaru's information, Madara immediately sent Jiraiya a secret letter. Although Jiraiya had taken Naruto away to train, they still had ways to exchange messages.
In his letter, Madara described Jūgo's power. Naturally, he said little about sage power or the additional information Orochimaru had given him, but he believed that all he needed to do was give Jiraiya a lead, and Jiraiya would tell him everything he knew.
After all, Madara was now the Hokage, and Jiraiya was loyal to Konoha. That made even a powerful man like Jiraiya his subordinate.
This was the benefit of having followers.
Before long, Jiraiya's reply arrived. In it, he told Madara everything he knew about nature energy.
Ninja could absorb and use nature energy. At Mount Myōboku, Jiraiya had learned how to absorb it and balance it with his own chakra and spiritual energy.
Once chakra and Nature Energy were combined, the result was what Orochimaru had called Sage Power.
After years of grueling training, Jiraiya could enter an imperfect Sage Mode, but he needed two sages to help him use it, and gathering the energy alone took five minutes.
Entering Sage Mode greatly enhanced a ninja's capabilities across the board, granting an explosive increase in strength.
If nothing unexpected happened, Jiraiya planned to teach Naruto Sage Mode in another year