Natural Energy

is energy that can be collected from the atmosphere and terrain. If one can collect the natural energy from around them and combine and balance it with the spiritual and physical energy that makes up their chakra, they can become sages, allowing them to use senjutsu and enter Sage Mode. This method can be taught by the inhabitants of Mount Myōboku and Ryūchi Cave.

The members of Jūgo's clan possess a special ability called Sage Transformation which causes their bodies to constantly absorb natural energy and allows them to regulate this energy to perform a myriad of shape-shifting feats. However, as they are unable to control the flux of power that comes with this, they are prone to randomly going berserk. Orochimaru also figured out how to utilise natural energy thanks to Jūgo's abilities and his discovery of the Ryūchi Cave, but was also unable to use it properly because he did not possess strong enough host bodies to use such power. Failure to control this energy leads to petrification or to the transformation into a snake, that is subsequently eaten by the White Snake Sage.

Trivia

 * The Ten-Tails is composed of and manipulates natural energy, thus, it (and by extension, its jinchūriki) can only be affected by natural energy-infused techniques.
 * In the anime, Gamamaru said that upon first landing on earth, the God Tree began absorbing the planet's natural energy.
 * There is also an anime-only kinjutsu developed by the Tsuchigumo clan, which draws natural energy into the user and then releases it in a devastating attack.