A "Sage" (仙人, Sennin) is someone who is able to utilise senjutsu (仙術; Literally meaning "Sage Techniques"), and has mastered the art of Sage Mode or someone given said title because of their renown for their great power, wisdom, or holy standing.
Main articles: Senjutsu and Sage Mode Senjutsu (仙術; Literally meaning "Sage Techniques") refers to a specialised field of techniques that allows the user to sense and then gather the natural energy (自然エネルギー, shizen enerugī) around a person.
Senjutsu practitioners can then learn to draw the energy of nature inside of them blending it with their own chakra (created from spiritual and physical energy within the shinobi), adding a new dimension of power to the sage's chakra, resulting in the creation of "senjutsu chakra" (仙術チャクラ, senjutsu chakura). This chakra cannot be seen by anyone other than those who have been trained in senjutsu. This new chakra enables the user to enter an empowered state called Sage Mode, which can then drastically increase the strength of all ninjutsu, genjutsu, and taijutsu. A person who is able to use senjutsu is called a sage (仙人, sennin). Currently, there are two known ways to learn senjutsu: One being to learn from the toads of Mount Myōboku as Jiraiya and Naruto have done, and the other from the snakes from the Ryūchi Cave where Orochimaru and Kabuto Yakushi learned it. The cursed seals that Orochimaru has used in the series also use senjutsu chakra.
A third form of senjutsu is also known, used by Hashirama Senju. Unlike previous methods, Hashirama doesn't display any animal traits. It is unknown where he obtained his senjutsu style from. Very few people are shown to have mastered senjutsu. This is because both learning and using senjutsu is not safe; death may easily occur while learning to use it. Fukasaku claims that the toad sculptures on Mount Myōboku are those who failed to master the art of senjutsu. Naruto Uzumaki, Kabuto Yakushi, Hashirama Senju, Orochimaru and Jiraiya are currently the only known human users of senjutsu. Other animals such as Fukasaku and Shima are also able to use it with the White Snake Sage and Great Toad Sage amongst others, being at least knowledgeable in it.
"Sage" can also refer to an individual renowned for their great power, wisdom, or holy standing.
- The Sage of the Six Paths was one of the most famous sages in the series, a legendary figure who discovered chakra, created modern ninjutsu, the one who saved the world from the Ten-Tails and was the first jinchūriki. It is unknown if he too was capable of using natural energy.
- Son Gokū's moniker: The Great Sage Equalling Heaven (斉天大聖, Seiten Taisei) also makes mention of being a Sage.