Natural Energy

is a form of energy that exists in the atmosphere and the earth. By gathering the natural energy in their surroundings and combining it with their own chakra, sages are able to enter Sage Mode and use senjutsu.

Overview
Natural energy circulates all throughout the world, but it is usually imperceptible. In order to use senjutsu, one must first learn to sense the natural energy in their surroundings and draw it into their body, which requires becoming "one with nature" by remaining perfectly still. To control the natural energy they absorb, the user must balance it with their own physical and spiritual energies, which together make up chakra, in order to create senjutsu chakra. If this balance contains too little natural energy, senjutsu cannot be used, but too much makes the user turn to stone; in the case of humans, they first turn into animals before petrifying. This process can be reversed if the absorbed natural energy is expelled before the transformation is complete, and Fukasaku wields a staff capable of beating the natural energy out of a person on contact. The toad oil of Mount Myōboku has the property of attracting natural energy, capable of quickly drawing it into a person when applied to their body, though it evaporates outside of the mountain's unique climate.

Members of Jūgo's clan possess special bodies that can absorb natural energy and undergo transformations. However, this power also causes them to go berserk without warning. Through his research, Orochimaru developed an enzyme from Jūgo's bodily fluids that is capable of inducing similar transformations in other shinobi. He is able to apply this power to others, alongside his own senjutsu chakra, in the form of cursed seals.

The Ten-Tails' vast power is described as feeling like natural energy itself; as such, it can only be sensed by those capable of using senjutsu. The beast is capable of manipulating natural energy, and by using its enormous chakra to disturb the natural energy in its surroundings, it can cause a series of natural disasters to occur. Natural energy is key to defeating the Ten-Tails' jinchūriki, whose body is immune to ninjutsu; Naruto Uzumaki describes this as fighting natural energy with natural energy.

God Trees grow by absorbing their planet's natural energy, draining power from the environment and its inhabitants alike until the planet becomes a desolate world devoid of any life.

Trivia

 * In the anime, the sound of natural energy being gathered to form senjutsu chakra is the same as the one used for the healing green chakra of the Mystical Palm Technique.
 * In the anime, the Tsuchigumo clan developed a kinjutsu that draws natural energy into the user and then releases it in a devastating explosion.
 * Despite not being a sage, Sasuke Uchiha demonstrated the ability to sense natural energy during his final battle with Naruto.
 * In the anime, Hagoromo Ōtsutsuki was instinctively able to sense the abundant natural energy flowing around Mount Myōboku, even prior to becoming a sage.
 * The White Snake Sage is capable of injecting natural energy into others using her fangs.