Sage

An individual who is able to utilize Senjutsu (仙術, Sage Techniques), and has mastered the art of Sage Mode is called a.

Myōbokuzan
Myōbokuzan (妙木山, Mysterious or Exquisite Tree Mountain) is the land of toads, the place where all the toads that Naruto, Minato and Jiraiya have summoned live. This is the place, where different characters, like Naruto and Jiraiya, learned to use senjutsu. There's a sacred fountain in Myōbokuzan where a special oil makes it easier for people to feel the natural energy, but if the person is not perfectly still becoming one with nature, he or she starts becoming a toad and eventually turns into stone.

Senjutsu
Senjutsu (仙術, Sage Techniques) refers to a specialized field of jutsu that allows the user to sense and then gather the natural energy 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) this results in the creation of "senjutsu chakra" (仙術チャクラ, senjutsu chakura).

Sage Mode
Sage Mode is a condition, when well - balanced use of chakra and natural energy leads to a sharp increase of a character's abilities and strength. However, it has quite many disadvantages.