Aang was not only the last Airbender for most of his life, but he was also the last Avatar (from a certain point of view). Beginning with Avatar Wan, Avatar: The Last Airbender‘s world had been protected and balance between the light and dark maintained for 10,000 years. This was a result of the spirit of light, Raava, binding with Wan, giving him the ability to bend all four of the Earth’s elements, even all at once. It was the power he needed to defeat and imprison the spirit of darkness, Vaatu.
Around the same time Wan became the first Avatar, people started to keep the powers they received from the ancient lion turtles and then began passing them down to their descendants. But as their powers were inherited, so, too, was Wan’s spirit as the Avatar; not long after his death, he was reborn in a new body as the next in line in the Avatar Cycle – a cycle that determines from which nation the next Avatar will come from. This cycle continued for thousands of years until after Aang’s death, when his spiritual successor, Korra, was born. Then something happened that broke the first cycle.
In The Legend of Korra season 2, Korra’s uncle and one-time Red Lotus member, Unalaq, successfully released Vatuu from his prison during the Harmonic Convergence, at which point he and Vatuu bound themselves together in the same way Wan did with Raava thousands of years before. Unalaq then fought Korra as the Dark Avatar and managed to sever her from Raava’s spirit. He then struck a depleted Raava multiple times, killing all of the Avatar spirits that existed inside of her. Doing so ended the first Avatar Cycle, ultimately making Aang the last Avatar.
Despite Korra rebinding herself with Raava and subsequently defeating Unalaq and Vatuu, not to mention restoring balance to the world once again, the damage had already been done. Korra had her powers back as well as her connection to Raava, but her tether to the previous Avatars was gone. She could no longer commune with any of them ever again, regardless of how hard she tried or if she was in the Avatar State. Unalaq may not have been able to throw the world into chaos, but he succeeded in ending the Avatar cycle that had begun 10,000 years prior.
Though unconfirmed, it stands to reason that Korra was the first in a new Avatar Cycle. Her successor, who would be an Earthbender (following the same pattern from before), should logically be able to communicate with her, given that Raava likely would be able to retain Korra’s spirit – she just wouldn’t be able to access the Avatar spirits that came before the Harmonic Convergence. Of course, Korra took precautions and chronicled her life as the Avatar for the next person in line, just in case. But in the end, Korra became the new Wan, and Aang was the last person in his line of Avatars.
