|Learned from||Lion Turtle (Aang) otherwise unknown|
Before the Avatar and the divide into the Four Nations, people used Energy Bending by bending the energy within themselves. The other four bending arts were founded later and over an extensive period of time and the overlaying application of knowledge that stemmed from Energy bending. Over time the art was almost completely lost and the only know creature that retains knowledge on how to bend this element is the Lion Turtle (and later Aang) - a creature that was born before time and space. Aang used his knowledge of Energy Bending to strip Ozai of his Fire Bending abilities.
The limitations and requirements of Energy Bending are vague and not well understood, but currently only the Avatar retains the capabilities to learn the bending skill due to the seeming requirement to enter the Avatar Mode in order to execute it. All that is known is that bending a person's life energy can impart them with knowledge instantly or remove one's bending completely. It differs from other bending arts as it puts the user at risk of death, tantamounting as to why so few have ever learned it in the past.