|"Raava! The only way to win is together."|
|— Wan urges Raava to merge with him.|
The battle during Harmonic Convergence was a confrontation that occurred in the Spirit World during the Harmonic Convergence of 9,829 BG. Wan and Raava fought against Vaatu to determine the fate of the spirit and physical worlds. The battle ended with a permanently merged Wan and Raava as its victor and Vaatu imprisoned within the Tree of Time, thereby marking the ending of the era of Raava and the beginning of the era of the Avatar.
Ages before this Harmonic Convergence, Vaatu broke through the divide that separates the physical and spiritual worlds, allowing spirits to roam it freely. Having won their previous duel, Raava kept Vaatu in check for almost ten thousand years, until Vaatu manipulated Wan into using firebending to free him from Raava's grip. When Wan realized the gravity of his mistake and after seeing the effects Vaatu had on peaceful spirits, he set out on a journey to receive all four bending arts from the lion turtles in order to help stop Vaatu. However, since no human had ever carried more than one element before, the air lion turtle decided that Raava must carry the element for him until he had mastered them, thus pairing them up. Together, they trained to master the four bending arts for nearly a year. Days before Harmonic Convergence occurred, Vaatu influenced spirits to become dark and wipe out a human settlement, which left Raava severely weakened. Shrunken down to the size where she fit Wan's teapot, she was in no condition to take on Vaatu herself.
In the Spirit World, Vaatu arrived through the Northern spirit portal, while Wan and Raava entered through the Southern. The dark spirit challenged Raava, but Wan stepped forward to defend her. Utilizing his firebending, Wan attacked Vaatu, though the dark entity easily evaded his blasts and retaliated with his tendrils and energy beams. Being no match for Vaatu on his own, Wan called upon Raava to help him by merging their energies. Now having access to all four elements, Wan managed to land a few hits. However, his merger with Raava put him in mortal danger, and even though he refused to give up and kept fighting, the side effects of hosting the light spirit for too long distracted him, enabling Vaatu to strike him with an energy beam and pin him to the ground near the Southern spirit portal.
When the planets aligned and the spirit portals merged, marking the beginning of the Harmonic Convergence, Vaatu became distracted by the prospect of ending the era of Raava and ruling for the next ten thousand year. Wan used this to his advantage and placed his hand on the spirit portal, using the augmented spiritual energy to permanently bond his own spirit with Raava's. Due to this bond, the Avatar Spirit was created, making Wan the first Avatar in the reincarnation cycle, and the side effects of hosting a spirit were no more. With his newfound strength in the form of the Avatar State, Wan began attacking once more and managed to trap the dark spirit in an elemental cage, before imprisoning him in the hollow of the Tree of Time.
Wan closed the Northern spirit portal from inside the Spirit World and guided the spirits in the physical world back to the Spirit World through the Southern portal and closed it as well, so that no human would ever be able to physically enter the Spirit World and free Vaatu. With the spirits no longer roaming the world, the lion turtles denounced their roles as protectors of humankind and stopped giving them the power of the elements. Wan, as the Avatar, would act as the bridge between the two worlds and use Raava's power to keep peace. The advent of the Avatar, the closing of the spirit portals, and humankind's separation from the protection of the lion turtles changed the world completely during the following ten millennia.
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Hedrick, Tim (writer) & Graham, Ian (director). (October 18, 2013). "Beginnings, Part 2". The Legend of Korra. Season 1. Episode 20. Nickelodeon.
- ↑ DiMartino, Michael Dante (writer) & Heck, Colin (director). (October 18, 2013). "Beginnings, Part 1". The Legend of Korra. Season 1. Episode 19. Nickelodeon.