Sage Mode

Sage Mode is an empowered state that can be entered by blending natural energy with one's chakra, creating senjutsu chakra. Sage Mode allows users to tap into the natural force of the world, opening up new techniques to them and allowing them to power up existing ones with the new senjutsu chakra.

Training
Sage Mode is known to be taught in two places: at Mount Myōboku by the toads and at Ryūchi Cave by the snakes. Users of Sage Mode must possess "extreme chakra levels" to invoke senjutsu. It is also important that their bodies be strong enough to support the increased power.

In order to enter Sage Mode, the gatherer must remain absolutely still in order to be one with nature and balance the natural energy with their own physical and spiritual energies. If the user puts too little natural energy into using senjutsu, the technique will not work. Conversely, if too much natural energy is taken in, their body will turn to stone forever; humans will also be transformed into whichever animal's school the senjutsu was learned from.

The toads of Mount Myōboku have devised several tools to make learning Sage Mode easier. By applying a special oil, the applicant's body will start passively taking in natural energy. This oil will evaporate if taken outside Mount Myōboku, thus rendering it useful only for learning purposes. The toads also have a special staff that, when struck with, knocks all the natural energy out of the gatherer, thus reversing any transformations before they can become permanent and the user turns to stone.

Attributes

 * Advantages
 * The user's physical strength, speed, stamina, reflexes, perception, and durability are enhanced.
 * The user's ninjutsu, genjutsu, and taijutsu become more powerful.
 * The user can manipulate the natural energy that surrounds them, turning it into an extension of their body to increase the reach of their attacks.
 * The user can sense chakra around them and can sense attacks without the need to see them.


 * Disadvantages
 * In order to gather enough natural energy to initiate the transformation into Sage Mode, the user must remain perfectly still, leaving them vulnerable. Users have at times been shown entering Sage Mode without this preparation.
 * Because the user needs to move during combat, the senjutsu chakra cannot be replenished, which means the user can't stay within this state for extended periods of time. Naruto states it is possible to lengthen the time limit.
 * These weaknesses can be bypassed with the Sage Art: Amphibian Technique, where one or more toads fuses with the user's shoulders and gather natural energy for them to use.
 * Another option is to employ shadow clones, having them gather natural energy elsewhere and then, when their natural energy is needed, having them disperse, transferring it to the original. This limits the number shadow clones that the user can have active at a time to five for as long as the clones are gathering natural energy, as any more than that would disrupt the clone's focus.
 * Kabuto Yakushi assimilated the DNA of Jūgo to replicate his clan's ability to passively absorb natural energy, thus allowing him to continuously collect the energy even while moving, bypassing these particular weaknesses.
 * If the user is also a jinchūriki that has achieved harmony with their tailed beast, they can drastically speed up their ability to gather natural energy in tailed beast mode to the point of only needing a few seconds to fully charge or recharge their sage chakra.
 * After Sage Mode has ended, the user appears to experience exhaustion.

Imperfected Sage Mode
Jiraiya is not able to properly balance his own chakra with natural energy, resulting in him using an imperfect form of Sage Mode. As a result of the imbalance, Jiraiya takes a number of toad-like traits when using Sage Mode: his nose grows bigger and gains warts, his teeth turn sharp, he grows a goatee, and acquires toad-like eyes. Because of these traits, Jiraiya doesn't like to use Sage Mode as it "displeased the ladies". Some of the physical alterations, such as the toad posture and the webbed feet, are beneficial and improve his manoeuvrability, and he can consciously manifest the alterations in order to take advantage of them.

Although he never mastered Sage Mode, Jiraiya still gains all the advantages of Sage Mode, although his enhancements are more limited by comparison to perfected practitioners.

Perfected Sage Mode
Users that can properly balance their own chakra with natural energy will not experience any animalistic transformations to their body. The one exception is a dark pigmentation around their eyes and the eyes themselves, which usually differ based on where the user learned Sage Mode:
 * Naruto and Minato have yellow, toad-like irides with orange pigmentation around their eyes.
 * Kabuto Yakushi has yellow, snake-like irides with purple pigmentation around his eyes that extends to his shoulder blades. His snake-like characteristics progressed further in Sage Mode with him growing four horns, leading him to state that metaphorically he had transcended from a "snake" to a "dragon".
 * Hashirama has yellow irides with red (black in the anime) pigmentation around his eyes that extends to his ears. He also has a marking on his forehead that resemble an eye.

Tailed Beast Sage Mode
After earning the Nine-Tails' cooperation, Naruto becomes able to combine Sage Mode with his Tailed Beast Mode. The red irides and slitted pupils characteristic of normal Nine-Tails transformations merge with the Sage Mode's eye pattern, creating a design reminiscent of a cross. The design of Naruto's shroud also changes. While using the combined form, Naruto gains simultaneous access to both forms advantages, such as by augmenting Tailed Beast Balls with senjutsu chakra. Advantages common to both forms (such as increases to strength and chakra reserves) are elevated beyond what either form grants individually.

Two years after the Fourth Shinobi World War, Naruto utilised this form against Toneri Ōtsutsuki and showed numerous improvements to the last usage he had against Obito. His power had improved to the point he was easily shattering Truth-Seeking Ball defenses (which he struggled to in the past even with a Tailed Beast Ball), he could not only keep up with Toneri's speed but outright blitz him at one point, and finally he could tank and overpower the Golden Wheel Reincarnation Explosion, an technique strong enough to completely cut the Moon in half. He was also able to fly in this form without needing Six Paths Sage Mode and could channel it all into a single fist for a devastating attack, enough to defeat Toneri with a single blow. Kurama, after obtaining his full power after the War was also increased to tremendous amounts thanks to Naruto's Tailed Beast Sage Mode, to the point where he could battle and overwhelm the Statue of the Ōtsutsuki Clan and launch it into space through the entire moon with a single Tailed Beast Ball.

Trivia

 * In Naruto the Movie: Blood Prison, the red coat Naruto wore during Pain's Assault appears when he enters Sage Mode and disappears when he turns back to normal.
 * The manifestation of animal like traits is a reference to the Japanese folktale Jiraiya Goketsu Monogatari, where Jiraiya, Tsunade, and Orochimaru came to study specific animal magic into their ninjutsu use.