The art of bending the four elements has been common knowledge for thousands of years, but there is a form that is far more mysterious and inscrutable, so much so that it has barely even been heard of by most in-universe scholars— Energybending. This style allows the practitioner to "bend" or manipulate the core energy of a person, their life force, in order to alter their spiritual content.
There is considerable information about Energybending in Avatar: The Last Airbender and its sequel that has been unexplored, from the source of its creation to the extent of its capabilities. What does this style entail? Where did it come from? What are the prerequisites to employ it?
10 It Is Older Than Bending The Elements
Energybending is a far more ancient than elemental bending, making it older than the Fire Nation, Earth Kingdom, Air Nation, and both the Water Tribes.
In fact, it is through this process that the four styles of bending (and their respective variants) developed over time, explaining why the notion of manipulating one's life energy, or spirit force, is considerably more crucial in terms of impact. In other words, there is no bending of any kind that does not have Energybending at its very core.
9 It Is Taught By The Lion Turtles
Before the first Avatar, Wan, changes the world forever by permanently keeping the gift of Firebending given to him by the Lion Turtles, these gentle giants present people with specific element control by employing the technique of Energybending.
This is confirmed by the Lion Turtle that meets Aang on the eve of his final fight against Fire Lord Ozai, who also claims that the artistry of this form had been lost for millennia (ever since they were supposedly poached to the extent of near extinction).
8 It Is Only Useable By Those With An "Unbendable" Spirit
As the Lion Turtle offers Aang the gift of Energybending, it affirms the notion that this ability is extremely risky, although if performed correctly, the rewards could be limitless.
The real test lies in its usage, because it is compulsory that the practitioner possess an "unbendable" spirit in order to bend another's, in the absence of which they "will be corrupted and destroyed." It almost seems like Aang is about to lose his spiritual battle with Ozai, given that he is inches away from turning fire-orange, but thankfully breaks free at the end.
7 It Has A Twisted Variant Called Bloodbending
For most of history, Bloodbending had either not existed, or its users hid their abilities to prevent themselves from the inevitable ostracism. In Republic City, around three decades post the Hundred Year War's conclusion, a Waterbender named Yakone displayed an inordinate level of skill in this dark art.
His son, Noatak, grows up to become the "resistance" leader, Amon, who learns how to destroy a bender's inner essence by twisting the spiritual value of their blood, consequently depriving them of the capacity for bending any element.
6 It Can Be Used To Counter Energy Effects
In The Legend of Korra, the Avatar is taught how to wield Spirit World energy to replicate the procedure originally devised by her uncle, Unalaq. For example, she Energybends the spirit capsules containing victims taken from the real world, thereby freeing them from bondage.
In addition, Korra instinctively tries to protect Kuvira (and Republic City) from the energy blast emanating out of the giant platinum mech's spirit cannon, a feat that rips a hole in the fabric between dimensions and creates a new spirit portal in the middle of town.
5 It Produces An Astral Projection
UnaVaatu strips Raava from Korra's body, dashing her against the rocks until the Spirit of Light dissipates into nothingness, which forever separates the Avatar from her preceding incarnations.
Instead of losing hope, she meditates within the Tree of Time, where she discovers that Energybending has the power to transform her physical body into an astral one. The resultant being is made entirely of light, and possesses the strength to fight on the same level, as well as deploy similar offensive tactics, as the Dark Avatar.
4 It Can Both Take Bending Away, And Also Restore It
As stated earlier, Energybending rewires the subject's vital force such that they lose access to their bending forever. Amon similarly utilizes Bloodbending to strip Korra, Lin, and several others of their powers, leaving them cheerless and desolate.
Nevertheless, Aang's spirit appears to Korra at the end of Book One, at which point he reverts Amon's action, restoring the three elements that had been lost in the earlier battle. Subsequently, the Avatar is able to repeat the process for everyone else.
3 Not Every Avatar Is Capable Of Energybending
While Energybending as a concept has existed since before recorded history, it doesn't mean that every Avatar has the knowledge or competence to wield this unique style. In fact, none of Aang's predecessors have been shown to bend the energy within humans.
More importantly, even Korra may not be able to use it to its fullest extent — when the new Airbender, Daw, begs her to strip him of his unwanted ability, she asserted that it was beyond her skill level. Se may have been lying, though, as she knows how important the Air Nation reconstruction project is to Tenzin.
2 It Has Ties To Buddhism
When the Lion Turtle "invites" Aang to the mysterious island, a chant plays in the background: Na Mu A Me Tuou Fu Shi Ne. This is a standard Mahayana Buddhist mantra that refers to the Amitabha Buddha.
This version is considered to be the source of all intelligence, perception, youth, generosity, and righteousness. His name refers to the eternal aspect of light, or radiance, due to his virtuous nature.
1 It Can Be Performed In The Spirit World
One of the most important facts about the Spirit World is that elemental bending does not work, leaving most practitioners completely powerless. Of course, this doesn't apply to benders who travel there via the spirit portals, but only for those who meditate themselves into the location.
Interestingly, Energybending does not have those restrictions, as Korra discovers when Raava asks her to control spirit energy in order to save Jinora and the tourists from the Spirit Wilds.