Battles during Harmonic Convergence (171 AG)

The battle during Harmonic Convergence was an apocalyptic battle between Avatar Korra and Dark Avatar Unalaq during the Harmonic Convergence of 171 ASC. The two Avatars engaged in a battle to decide the fate of the Spirit and physical worlds, which eventually ended with Korra's victory and Unalaq's death. The conclusion of this battle marked the end of the Water Tribe Civil War and the dark spirit incidents.

Prelude
For several decades, the world had been left severely unbalanced spiritually due to the occurrence and aftermath of the Hundred Year War. Many spiritual areas across the planet had become tainted, while old traditions to appease spirit were abandoned and forgotten. This enraged the spirits, allowing Vaatu, the spirit of darkness, to grow increasingly stronger as he fed off their negative energy. As Harmonic Convergence drew near, Vaatu's influence grew to the point where he could directly influence both the Spirit World and the mortal world. Starting around 151 ASC, many spirits turned dark and began openly assaulting humanity at various locations across the globe. The number and aggressiveness of dark spirits grew dramatically as time passed, especially around the South Pole. Chief Unalaq took note of these various attacks and used this opportunity to intervene in the South.

During the Glacier Spirits Festival of 171 ASC, Unalaq manipulated Korra into assisting him in opening the spirit portal, though after she discovered her uncle's true motives, namely to free Vaatu, she refused to assist him in opening the Northern portal. However, when Unalaq captured Jinora's spirit in the Spirit World and threatened to destroy her, Korra was forced to open the Northern portal. Following her return from the Spirit World, Korra informed her allies of Unalaq's true motives. Still unable to convince President Raiko to assist against Unalaq, despite the clear implications that the world would end should she fail, she set out on her own with Team Avatar, Bumi, Kya, and Tenzin on a battleship Varrick provided, to stop Unalaq and save Jinora.

Beginnning
Arriving at the South Pole, Korra learned form her mother that her father had been captured and many rebel soldiers had been badly injured. Senna also warned her daughter that the southern portal was heavily guarded by Northern Water Tribe soldiers, as well as dark spirits. Given the idea from one of Bumi's stories, the group planned an assault from above. They split into separate groups; Tenzin, Bumi and Kya were to ride with Korra on Oogi to get into the portal while Bolin and Mako would join Asami and create a diversion.



Bolin, Mako, and Asami boarded a biplane, but despite their attempt to execute a surprise attack, the trio found the army assembled and ready to defend the portal. Asami maneuvered through the assault launch while Mako and Bolin provided cover by bombarding the army with their bending. Desna and Eska both attacked the plane, and were able to bring it down. The trio was quickly captured and brought to a tent where Tonraq was also being held.

The second group on Oogi approached the portal, but the bison was soon attacked by numerous dark spirits, who were attaching themselves to him, bringing the bison down. Korra, Kya and Bumi attempted to fight off the spirits dragging Oogi down. As a result Bumi had fallen off the bison, but had been able to drag a spirit down with him, while Oogi crashed into the ground, rendering each group member unconscious. Korra awoke in the tent where Tonraq was being held with the rest of the others with whom she attempted to enter the Spirit World. Unalaq entered the tent and revealed his ultimate goal: to fuse with Vaatu and become a Dark Avatar. Despite his brother's pleas to turn back, Unalaq still intended to continue with his plan, instructing Desna and Eska to guard the group as he walked out.



Bumi, having not been captured, disguised himself as a Northern soldier and entered the camp. He attempted to calm the spirits by playing his flute after seeing the success of this method on another spirit. Instead, the spirits were only further angered, and they began to chase and attack him. Bumi hid himself inside a mecha tank, but the spirits managed to enter it and take control. In the ensuing chaos, Bumi unintentionally destroyed the entire camp. Inside the tent, Korra attempted to reason with her cousins by telling them what would happen should their father succeed in his plan. Desna denounced her and defended his father's belief. Bumi suddenly arrived with Naga, the latter of whom proceeded to knock out both twins. He freed the rest of the group, allowing them to make their way to the spirit portal. There the group split up again; Korra had Asami take Tonraq back to Katara, while Tenzin, Bumi and Kya were to find Jinora, and Bolin and Mako were tasked with engaging Unalaq in order to allow Korra enough time to go and close the portals.

Entering through the portal, the group was engaged by spirits whom Unalaq directed toward them. Korra had sent Tenzin and his siblings off to find Jinora before entering the Avatar State to disband the dark spirits with a large blast of air. Mako and Bolin held Unalaq while Korra reached the southern portal. During her attempt to close it, Korra was blown backward by a pulse of energy as Harmonic Convergence began. Unalaq looked on with a crazed smile as a purple haze stretched across the poles and the entire world. Vaatu used the amplified spiritual energy to break free from his prison, laughing triumphantly as he approached Korra.



Vaatu announced the inevitability of his release and declared that Harmonic Convergence had arrived once again. Korra resolved to prevent Vaatu from fusing with Unalaq to create the Dark Avatar, fending off the dark spirit with firebending before using airbending to send Unalaq through the southern spirit portal to the South Pole. She instructed Bolin and Mako to ensure that Unalaq did not reenter Spirit World, before promptly attacking Vaatu once more. Assaulting Vaatu with her bending, Korra landed powerful blows on the dark spirit. The Avatar, however, was subdued after being hit by Vaatu's energy beam and was ensnared with vines which he created. After struggling to free herself for a period of time, Korra used firebending to incinerate the vines and launched a devastating assault against the spirit before trapping him in an elemental sphere. Before she could fully imprison him once again in the Tree of Time, she was hit by a water blast from Unalaq, allowing Vaatu to break out of the elemental sphere. As she attempted to retaliate, Korra was hit again by another water blast, incapacitating her. Mako and Bolin arrived seconds later, only to find Korra on the ground. The two were quickly encased in ice by Desna and Eska, thereby stopping them from moving forward.

The Dark Avatar


Unable to act quickly enough, Korra watched helplessly as Vaatu and Unalaq merged. He quickly maneuvered himself to one of the spirit portals. Using the spiritual energy, Vaatu and Unalaq permanently fused together, forming the Dark Avatar. Announcing their unity, Unalaq declared the beginning of a new era for spirits and humans which would be lead by him as the new Avatar. Korra denounced his declaration by reclaiming her position as the old Avatar, stating that her era had not yet ended and enforced her statement by entering the Avatar State. The two promptly collided in a battle which would decide the fate of the world.

Making their way out of the Spirit World, Korra and Unalaq continued their battle around the southern portal. Unalaq had managed to knock Korra off her air spout, and had trapped her in a fissure on the ground, before beginning to crush her and declaring her life was over. Raava demanded Korra not give in to ten thousand years of darkness, inspiring the Avatar to make her way out of the fissure upon directly connecting to Raava's essence. The two resumed their battle, with Korra insisting Unalaq's inevitable defeat.

After being freed by Desna and Eska, Mako and Bolin exited the spirit portal to see Korra and Unalaq continuing to combat one another. Korra was able to bring down Unalaq, but before she could subdue him, Vaatu emerged from Unalaq and quickly attached himself to Korra. He proceeded to rip Raava from Korra as she collapsed to the ground. Unalaq quickly trapped Raava in a sphere of water upon being repossessed by Vaatu.



Despite their efforts to save Raava and Korra, Bolin and Mako were overwhelmed by Unalaq's bending and knocked unconscious. Korra, still lying on the floor, watched helplessly as Unalaq slammed Raava against a boulder. He promptly hit the spirit with a blast a water. As Korra attempted to get up, she felt the effect of the impact as Aang's spirit disappeared. As Unalaq continued to viciously assault Raava with his waterbending, the Avatar spirits began to disappear at an ever increasing pace. Finally, Unalaq formed one last torrent of water. As Korra weakly outstretched her hand to Raava, she watched in horror as the last impact destroyed both the light spirit, and the last Avatar spirit, Wan. Korra subsequently lost consciousness, while the Dark Avatar ascended into a massive form that bore characteristics of both beings of whom he was constructed, while Mako, Bolin, Desna, and Eska all watched in shock. The Dark Avatar announced the beginning of ten thousand years of darkness before using the spirit lights to transport to Republic City.

Light versus Dark


Arriving in Republic City in a blinding light, the Dark Avatar landed in the Yue Bay. Almost immediately, he was bombarded by a United Forces fleet under General Iroh's command. The Dark Avatar walked toward the fleet, unfazed by the hits. He subsequently raised an enormous wall of water and sent it forward, decimating the fleet. He promptly walked over to Aang Memorial Island and hurled the statue of Avatar Aang into the bay. He also shot down the airship carrying President Raiko and Lin Beifong with a massive energy blast, and filled the city with destructive vines.

Meanwhile, Tenzin, Kya, and Bumi found Korra, Mako and Bolin unconscious and carried them back into the Spirit World to be healed in a pool of water. When they awoke, Korra revealed that Unalaq had destroyed Raava, severing her connection to her previous lives and rendering her the last Avatar. While Korra grieved over the loss of her past lives' wisdom, Tenzin used the wisdom Aang imparted to him on letting his attachment to his wrong perception of himself go, and encouraged her by stating that she had power beyond the Avatar Spirit.

Taking her to the Tree of Time, Tenzin explained that before it held Vaatu, its purpose was to be the location where the ancients would meditate to connect with the cosmic energy of the universe. Inside, Korra saw her memories portrayed by the tree's power. Tenzin continued by saying that the tree "remembers all", and it was said that its roots bound the spirit and physical worlds together, and told Korra that she was not defined by Raava, but by her "inner spirit", referencing her strong and unyielding personality. The tree projected memories of Avatar Wan, whom Tenzin pointed out to be just a regular person before fusing with Raava, and stated that Wan became a legend because he was a compassionate and courageous person, not just because of Raava's influence. Upon spotting an image of Unalaq assaulting Republic City, Tenzin encouraged Korra to connect to the cosmic energy by bending the energy within herself.

Korra subsequently spotted a memory of Raava explaining to Wan about the nature of light and darkness - neither one can exist without the other and should either one be "destroyed", either spirit would gradually be reformed and be reborn from the other. Using this knowledge, Korra decided to meditate inside the Tree of Time. She connected to the cosmic energy inside her and energybent an astral projection of herself. The projection exited the hollow of the tree and used the spirit lights to head for Republic City in pursuit of the Dark Avatar.



Back in Republic City, the Dark Avatar was nearing victory, but Korra's spirit appeared from the sky and rammed him, knocking him into the bay. He rose and unleashed an energy blast; however, Korra summoned a beam of her own which overpowered and blasted him back. The Dark Avatar tried to subdue Korra with his tendrils, but Korra was able to grab a hold of them, allowing her to gain the upper hand, and subsequently slammed the Dark Avatar into a nearby mountain. Pinning her foe down, Korra frantically searched for Raava inside his body, but to no avail. Korra became disheartened, giving the Dark Avatar an opportunity to entangle her with his tendrils, proclaiming that the light spirit that she was looking for was gone, before striking her with a close-range energy blast.

Meanwhile, in the Spirit World, Korra's allies were confronted by a large horde of dark spirits advancing on the Tree of Time. Having realized that the spirits were coming for Korra, all four benders of the group launched their respective elemental attacks against the dark spirits in order to defend the Avatar. Eventually, Desna and Eska, having decided to betray their father, joined the battle, coming just in time to save Bolin.

Back in Republic City, the Dark Avatar was able to subdue Korra's astral projection, and began to use the spiritual waterbending technique in order to destroy her. Just as he was about to do so, proclaiming that once she was gone he would become the one true Avatar, Jinora descended from the sky in a brilliant light. Carrying a small orb of light, she released it, showering her surroundings in a brilliant glow, breaking the Dark Avatar's concentration, thus freeing Korra's spirit, and illuminating a small orb of light deep inside the Dark Avatar.



Backing away, the Dark Avatar was shocked to notice that a light had formed inside him. Realizing that the light was Raava, Korra's projection ran over to the Dark Avatar and punched into him submission, allowing her to rip Raava from within him. She promptly performed the spiritual waterbending technique to purify the Dark Avatar Spirit, causing him to dissipate. Raava subsequently informed Korra that they must return to the Spirit World to reunite as Harmonic Convergence was nearing its end. Using the spirit light, Korra performed the jump back to the Spirit World.

In the Spirit World, Korra's allies continued to vainly battle the dark spirit horde in order to protect Korra, pushed into the hollow of the Tree of Time. Just as they were about to be overwhelmed, Korra's astral projection returned, and her impact instantly dissipated all the spirits. Exiting the hollow of the tree, they were greeted by Korra's projection, who released Raava and Jinora's spirit from her hands. Jinora descended toward her father before returning to her physical body. Korra's astral projection subsequently dissipated and returned to her physical body. She re-awoke and was picked up by Raava, where they rode toward the overlapping spiritual beams. There, using the spiritual energy, they reconstituted the Avatar Spirit just as Harmonic Convergence ended. She subsequently descended toward her friends, where they congratulated her on her accomplishment.

Aftermath
By defeating both Unalaq and Vaatu, Korra effectively ended any plans they had in store for the world. She also removed the possibility of another person joining with Vaatu, and by purifying the Dark Avatar Spirit, she put an end to the cycle that would have occurred, thus preventing the chance that another Dark Avatar would be born into the world. Vaatu's dissipation and Unalaq's death brought an end to both the Dark Spirit incidents and the Water Tribe Civil War, respectively. However, since Raava was removed from her and destroyed, Korra lost all connection to and potential knowledge from previous Avatars. Also, the Dark Avatar's assault on Republic City caused an unprecedented amount of damage to the whole metropolis, with a large number of vines wrapping around the various buildings and skyscrapers around the city, as well as the statue of Avatar Aang having been detached and thrown into Yue Bay. However, Korra was successful in preventing the world from being plunged into ten thousand years of darkness, and decided that, for the first time in ten millennia, the spirit portals would be open, allowing for humans and spirits to freely move between the two realms.