Growing up, Kya and her older brother,Bumi, enjoyed teasing and roughhousing their younger brother, Tenzin. Although the three siblings maintained a relatively healthy relationship, Kya and Bumi became distant with their father due to his fixation on saving the world, preserving the Air Nomad culture and training Tenzin, the only other airbenderin the family. Consequently, Kya developed a stronger connection with Katara, who taught her waterbending. In the process, Kya had developed her waterbending andchealing abilities to proficiency.
As she became older, Kya traveled around the world, which Tenzin described as "finding herself". However, after Aang's passing in 153 AG, Kya returned to the Southern Water Tribe to tend to her grieving mother, as her brothers were occupied by their respective professions.
In 171 AG, Kya attended the Glacier Spirits Festival in the Southern Water Tribe. She awaited the arrival of her brothers at the dock, eagerly greeting her niece,Jinora, while stating that Tenzin did not bring his family around nearly enough. As she greeted her younger brother, she playfully put forward Tenzin's fear of her as the reason why they never visited. She later attended the royal banquet in honor of Chief Unalaq, during which she seemingly came to Tenzin's rescue when Bumi was teasing him, though used the opportunity to jab at him as well. That night, Kya was awoken by the attack of a dark spirit, though by the time she arrived, the entity had already been calmed by Unalaq. She witnessed how Korra thanked Tenzin for his tutelage thus far, though decided that she no longer required his services. Some time later, Kya, together with Bumi and Katara, came to see Tenzin off as he prepared to take off toward the Southern Air Temple. She ended up accompanying her younger brother at the insistence of their mother, joyously expressing her eagerness to see the "laid back vacation Tenzin"
Arriving at the Southern Air Temple, Kya and Bumi were not treated with the same respect as Tenzin and his family, as one Air Acolyte did not even know that Aang had any other children, believing Kya and her brother to be the servants. They grew even more annoyed when the woman apologized to them for their lack of airbending abilities.
During her stay at the Southern Air Temple, Kya used her time to relax and joke around with her brothers. However, when Tenzin expressed his joy over having his siblings around, as it reminded him of all the vacations they took as children with their dad, Kya grew annoyed, reminding him that she and Bumi were never part of those vacations. However, her mood brightened when Jinora and Meelo arrived as well. When it was discovered that Ikki had run away, she suggested that she and her two brothers would search for her together.
By dusk, however, the siblings still had not found any trace of the young airbender. When Tenzin mused that Ikki's disappearance was probably his fault, Kya was quick to agree with him, explaining that he had likely been too busy with his duty to Republic City that he had forgotten to spend more time with his children, just like Aang had been with them. She chided Tenzin for being under the false impression that they all had had a happy-go-lucky childhood, when that had not been the case for her and Bumi. As Tenzin attempted to avoid talking further about the subject, Kya and Bumi mocked him for his "classic airbending technique" of evading things when they get tough.
Even after the night had fallen, the trio continued their search for Ikki, with Bumi entertaining his siblings with grandiose stories over his past search and rescue missions. As her brothers began to bicker, an annoyed Kya left them to it and walked on, finding the first trace of her niece, namely footprints leading down a trail next to a waterfall. As Kya and Tenzin moved to follow the prints, Bumi suggested that they descend via the waterfall as that would be much quicker. Kya opposed the idea initially, stating that the darkness and the slippery rocks would make it a very dangerous journey, but after Bumi confidently stated that if he, a nonbender, could make his way down, it should not be any trouble for two benders, she and Tenzin swiftly made their way down using their respective bending arts. Witnessing Bumi's struggle to get down, she mockingly called up to him that he had been right to say that descending the waterfall was faster though grew worried as the retired commander slipped and fell the entire way down into the water.
Kya started to heal the injured Bumi, though quickly got into an argument with him over his immaturity over their bending abilities, chastising him for failing to accept that he could not do everything a bender could. As he dismissed her, Kya stopped healing him and let the water drench him, wishing him luck healing himself with his "special nonbending powers". However, when Tenzin stated that he had to be the responsible one of the trio, Kya grew annoyed with him as well, refuting his claim by stating that she was the only one who had taken on the responsibility of taking care of their mother when their father had died, though Tenzin minimized that responsibility by pointing out that she had moved all over the world for years before that, arguing it had been time for her to settle down anyway. The argument quickly escalated, turning back to the core issue that Tenzin was heavily favored by Aang and made it his sole responsibility of carrying on Aang's legacy, as opposed to doing that with his siblings. Irritated, she stated that she never should have accompanied Tenzin on his vacation, something her brothers swiftly agreed to. Kya and Bumi curtly agreed to go back to the temple to see if Ikki had returned, while Tenzin kept looking on his own.
The next day, Kya found Bumi in the air temple sanctuary, looking at their father's statue. Hearing her brother's unanswered search for their father's approval, she hugged him, assuring the ex-commander that Aang would most definitely be proud of him.
After Tenzin returned with Ikki, he apologized to Kya and Bumi for his behavior. In turn, she also apologized for dumping her frustrations about their dad on him. Believing her brothers would like to see the picture Katara gave her before they left the Southern Water Tribe of them with their parents when they were younger, she showed the item to them, and they huddled around to look at it fondly.
A few days later, Kya witnessed in awe as her oldest nephew orchestrated a ring-tailed winged lemur air show.
Having arrived at the Eastern Air Temple, Kya engaged in a discussion with her older brother, calling him out to be a liar for claiming that he once won a rock-throwing contest against an earthbender. Their conversation was cut short when Tenzin announced their itinerary for the day. However, before they could embark on the tour of the temple, Korra arrived, pleasantly surprising everyone. She was shocked to learn the events they had missed by being closed off from the outside world.
When it became apparent that Korra needed to enter the Spirit World, Kya accompanied Tenzin, Korra, Bumi, Jinora, Ikki, and Meelo to several locations while the first two attempted to cross over. After witnessing them fail to cross over a first time by meditation accompanied by melodious ringing of a bell, they moved on to another location, where Kya placed incense sticks around the meditating duo. When Tenzin failed once again to cross over, growing annoyed over the smoke thwarting his attempt, he blamed his sister for having set up the incense wrong, prompting her to defended herself by pointing out that she followed his instructions. As they moved on to the next location, Kya became intrigued by Jinora's behavior, who was seemingly chasing something, though when she asked her niece about it, she was brushed off, leaving Kya to her own suspicions.
Kya returned to the air temple, where she was shocked to hear Tenzin's confession that he had never been to the Spirit World before. When Korra emphasized her urgency to get to the Spirit World, Kya acted upon her suspicions and pushed Jinora to reveal her secret, namely that she had been conversing with spirits. As the dragonfly bunny spirits appeared on Jinora's urging, much to everyone's amazement, Kya corrected Tenzin's earlier statement that Jinora was allegedly too young to know about spiritual matters.
As Kya, Bumi, Tenzin, Jinora, and Korra followed the dragonfly bunny spirits to an ancient meditation circle, Kya reassured Jinora, who was worried that her father was mad at her, that Tenzin was not mad but merely suffering from a bruised ego, and she continued to follow Jinora and Korra's conversation about Avatar Wan.
As they arrived at the location, Kya witnessed Tenzin perform a cleansing ceremony. However, the ritual drew out a swarm of bat-like dark spirits that promptly attacked them. She protected Jinora with her body until Korra used Unalaq's spiritbending technique to calm them down, impressing her. Korra and Tenzin's subsequent reconciliation moved Kya to tears.
Kya spent the remainder of the day waiting with the others while Tenzin attempted to cross over to the Spirit World through meditation. When it became apparent that it was not going to work, she told her brother that since he was not ready to guide the Avatar, he should stop being so stubborn and let Jinora fulfill her destiny by guiding Korra into the Spirit World. As Korra and Jinora crossed over, Kya and her brothers remained behind to keep their bodies safe until they returned.
As they sat around a campfire next to the girls' bodies, Kya tried to comfort her younger brother, who was worrying about Jinora being in the Spirit World, by pointing out that his daughter was smart and had a strong connection to the spirits. After Bumi took offense to Tenzin's suggestion that Korra and Jinora would be defenseless without their bending, Kya interjected that Bumi's situation was different due to his positive attitude. She and Bumi were subsequently advised by Tenzin to get some rest, who offered to take first watch. Before lying down, Kya told him to wake them up if he needed some company.
The next morning, Kya was awoken by Korra's sudden return to the physical world without Jinora. They all returned to the Eastern Air Temple and relayed her eldest child's faith to Pema, before traveling back to Republic City, where Kya was among those witness to Mako's exoneration and release from prison.
Kya later accompanied her brothers and Team Avatar on the Zhu Li, a battleship provided by Varrick, back to the South Pole. During that time, she used her healing abilities to sustain Jinora. After the healing session was over, she rejoined her brothers and Team Avatar on deck though was surprised to hear Tenzin's aggressive plan of action.
Upon hearing news of the Southern Water Tribe rebels' defeat, the party arrived at the White Lotus compound, where Kya passed Jinora to Katara's care, noting that despite her best attempts to keep Jinora's energy flowing for almost a week, there was nothing more that she could do to prevent her niece from slipping away, placing her hope in the abilities of her mother. They discussed how to break through the Northerner blockade surrounding the Southern spirit portal. Asamicame up with a plan for herself, Mako, and Bolin to cause a diversion with abiplane while the others fly into the portal on Oogi.
As the party began their assault, the Northern army was revealed to be supported by dark spirits, who attacked Oogi, weighing him down. Korra, Kya, and Bumi attempted to ward off the dark spirits, but there were too many, ultimately leading to their capture save for Bumi. Brought to a tent, Unalaq mockingly congratulated them all for procuring "front row seats to the beginning of the new world order" under his leadership as the Dark Avatar. However, after the tribal chief took his leave, Kya remained optimistic, as Bumi had evaded capture, and was proven correct when he and Naga eventually freed them all. While Asami returned to the compound with Tonraq, Oogi, Naga, and Pabu, the others ventured into the portal. Tenzin, Kya, and Bumi split off to find Jinora while Korra and the others fought Unalaq.
As the three siblings wandered the Spirit World, Bumi futilely called out for Jinora's spirit. He suggested that they employ his tracking skills, but Kya disproved his plan by pointing out that spirits may not even leave footprints. She instead tried meditating before pointing off to her left, claiming that Jinora was in the direction of the spiritual energy she was sensing, but Bumi refuted that there was spiritual energy in every direction. Tenzin decided they needed a spirit guide, but the dark spider spirit he attempted to recruit was not exactly friendly, chasing the trio off a cliff.
Completely lost, they started going around in circles before encountering Iroh's spirit, whom they had not seen in forty years. After explaining their dilemma, Iroh gave them cryptic advice, which gave Tenzin insight on how to find Jinora. Kya and Bumi were led back to the dark spider spirit by Tenzin, who provoked it, prompting the spirit to capture the siblings and take them to the Fog of Lost Souls. Gazing upon the fog, Kya voiced her confusion, as she had been under the impression that the spirit would take them to a prison, though before the spirit threw in, Tenzin assured her that it was one.
Wandering the fog, they searched for Jinora while Tenzin urged Kya and Bumi to remain focused in order to prevent the spirit from driving them mad. After Kya inquired as to how long an individual could remain trapped in the Fog of Lost Souls, they came across Zhao, who mistook Tenzin for Aang, forcing Kya and Bumi to throw him off.
The siblings later tied themselves together to avoid getting lost, but they slowly succumbed to the fog's influence. Bumi became convinced that he was surrounded by cannibals, and Kya forgot she even had a family and they both ran off. After Tenzin was able to accept his self-doubts, the fog dissipated and he collected both Jinora and siblings. As soon as they exited the mental prison, Kya and Bumi started to regain their bearings. However, Jinora sensed the destruction of Raava. After passing a light spirit butterfly to guide her father, aunt and uncle out of the Spirit World, she vanished.
Kya and her brothers subsequently returned to the physical world, where they found Korra, Mako, and Bolin unconscious in the snow and carried them back to the Spirit World, where Kya used spirit water to heal them. As Korra lamented her failure to stop Unalaq and Vaatu from fusing into the Dark Avatar and protect Raava, Kya encouraged Tenzin to help the Avatar, resulting in Korra manifesting her spirit in an enormous size and vanishing through the combined spirit portal.
This left her physical body unprotected, however, prompting Kya, her brothers, Mako, and Bolin to defend it and themselves against the dark spirits that converged on the Tree of Time. Despite the help of Desna and Eska, the group was overwhelmed and forced into the tree's hollow. As they were on the verge of being overrun, Kya and the others were saved by Korra's returning spirit. As they all exited the tree, they witnessed in awe how Korra fused with Raava, recreating the Avatar Spirit.
After their return to the physical world, Kya witnessed Korra announce the end of the Water Tribe Civil War with the Southern Water Tribe's independence, Tonraq's election as the new chief, and a new age where humans and spirits would co-exist.
Two weeks later, Kya was helping Pema take care of Rohan on Air Temple Island when Ikki called for her father. She, alongside Pema and Jinora, hastily followed Tenzin outside to find out what the problem was, though when Bumi started telling about his ventures with Bum-Ju and claimed he could airbend, she promptly turned to go back inside. During dinner, an irritated Kya refuted Bumi's claim that his napkin moved by pointing out that he had blown on it. However, she looked on in shock when Bumi subsequently airbent.
The next day, Kya and the others watched as Bumi tried, unsuccessfully, to airbend on command. While Korra, Tenzin, and Ikki mused over possible reasons for the revelation, Kya told her oldest brother that she had been feeling changes in his aura since Harmonic Convergence, though she was annoyed when he snapped at her for not telling him earlier.
That evening, Kya remained on the island while Korra, Tenzin, and Bolin traveled to Kyoshi Bridge to help the Republic City Police deal with Daw, another new airbender.
After several reports spread of airbenders appearing throughout the Earth Kingdom, Kya watched as Asami landed a Future Industries airship on the island in order to take Tenzin, Bumi, Jinora, and the rest of Team Avatar to Ba Sing Se. She announced that she would remain on the island with Pema and happily picked up Rohan, asking him if he was excited to spend time with her while jiggling up and down. Dishearted when he threw up on her, she used her waterbending to remove the mess off her clothes, while Pema stated that Rohan liked her.
When Ikki and Meelo complained about the unfairness that they needed to stay on the island while Jinora was allowed to accompany the group to Ba Sing Se, Kya defused the tension by telling them that they were needed on the island to provide guidance to new airbenders around the city, deeming it to be an important task as well. She later waved goodbye as the group departed on the airship and spent the following days helping the new airbenders of Republic City get settled in on the island.
Some days later, Kya was conversing with Pema when Ikki and Meelo came into the dining hall to show Daw and two new airbenders around the premises, and later on, her youngest niece excitedly announced the arrival of another airbender to her, Yorru.
While nearing dusk, Kya approached Meelo training the new airbenders at the rotating gates to announce that Tenzin had found other new airbenders and requested for them to meet at the Northern Air Temple to commence formal training. Despite being confused by Yorru's inquiry about whether the Avatar would join them, she replied that Korra decided to separate from Tenzin during their travels.
As night fell, Kya found Ikki talking with Yorru in Tenzin's study. Suspicious of the stranger, she encouraged her niece to head to bed before questioning Yorru, remarking that he had extensive knowledge of the Air Nomads for someone who was new to the ability. Musing over the fact that he had been able to move through the gates like an expert, she inquired about his origins, though when he brushed her off by saying that she probably had never heard of the small village up north, she realized that Yorru's true identity was Zaheer and attacked him with ice bullets, which he swiftly deflected using Tenzin's airbender staff. As Zaheer attempted to fly away, Kya called for reinforcements and used a water tentacle to grab and ground Zaheer, whom she subsequently attempted to trap in ice, albeit unsuccessfully. To prevent his escape, Kya conjured a small wave to attack Zaheer, who knocked her down with an air blast. Two firebending sentries attempted to aid Kya, who tried once more to subdue Zaheer using a pressurized water drill, which the airbender evaded before retaliating with an air bullet from his staff and fleeing the scene.
The next day, Kya accompanied Pema, Ikki, Meelo, Rohan, and the new airbenders to the Northern Air Temple. Upon disembarking, she informed Tenzin of her clash with Zaheer, who managed to escape with the locket of GuruLaghima. As Tenzin helped her with the correct pronunciation of the guru's name, she remarked that she could never remember all the gurus and inquired if Tenzin remembered the "long and boring" story about the one who never ate.
Some time later, Kya was meditating with Opal and the other new female airbenders when Bumi suddenly came bursting through the doors, saying that Zaheer had arrived at the temple and that they needed to evacuate immediately. Before they could reach the bison stables, however, Kya and the others were forced to stop and comply with the Red Lotus' orders when Ming-Hua had captured Opal and was threatening to kill her.
After being rounded up in one of the temple's courtyards with everyone else, Kya comfortingly held Opal while Zaheer told them they would be used as leverage to get to Korra and would be unharmed as long as they cooperated. After Tenzin blew back Zaheer, Ming-Hua, and Ghazan, Kya was asked to fight alongside her brothers in an attempt to give the others time to flee the temple. Bending water from a fountain to form a ring around her, she prepared to engage Ming-Hua.
The two waterbenders faced off, trading several blows and shifting between deflecting, evading, and attacking. Kya managed to break off Ming-Hua's ice blade appendage and threw it back at her, though the armless bender grabbed the blade and sent it back with two more, knocking Kya against the wall with the last fragment of an ice bullet. However, when Ming-Hua charged her to finish her off, Kya managed to briefly get the upper hand by blasting her aggressor off the temple's balcony. The victory was short-lasted, however, as Ming-Hua used the water of Kya's attack to create six water arms as opposed to her regular two. Overwhelmed by the extra attack force, Kya was pushed back into the temple, where she ended up back to back with Bumi, both panting heavily.
Despite now fighting together, the siblings were forced on the balcony themselves now under a barrage of water, earth, and lava and were eventually tossed over by an earth pillar attack. Kya was saved from plummeting to her death by Bumi, who had used his airbending to bring them close enough to the ledge to find a handhold. However, their new situation brought them directly into the line of sight of P'Li. Realizing they were a perfect target for the combustionbender, Kya urged her brother to let go, reasoning that they might as well risk the fall against certain death. Tumbling down through trees and over rocks, the siblings eventually came to a halt on a mountain path, where they remained unconscious, though alive.
Badly injured, Kya and Bumi were found by the Red Lotus and taken to a cave-complex a few miles away from the temple along with the rest of the temple's inhabitants, where they were all shackled to the floor by their wrists. After Team Avatar burst through the wall and rescued them, she was hoisted up and supported by Otaku and a female airbender to make it outside, where she was placed against a rock from which she could spectate the battle between Korra and Zaheer. After Zaheer had been incapacitated, Kya witnessed how Suyin saved the Avatar by extracting the mercury from her body.
Kya returned home with everyone, where she received proper care. Two weeks later, although still leaning heavily on a crutch for support, she witnessed Jinora's anointment ceremony as a master airbender, during which her tattoos were revealed.
After Jinora's anointment ceremony and no longer in need of her crutches, Kya waited with Tonraq, Senna, and Naga on the ferry dock of Air Temple Island, while Korra said goodbye to Tenzin, Jinora, and the rest of Team Avatar. She later boarded the steamship heading toward the Southern Water Tribe together with Korra and her family, and she looked on while they were being waved off by the group.