Katara grew up as the mature, motherly figure of her family and tribe. She was the only waterbender left in the South Pole. When Katara was eight years old, her mother was killed in a Fire Nation raid. She resigned herself to cooking and cleaning duties while her brother, Sokka, trained to become a warrior.
At the age of twelve, Katara saw the departure of her father, Hakoda, and the other tribesmen to the Earth Kingdom to participate in the war effort against the Fire Nation. This left her, alongside her brother and grandmother, Kanna ("Gran Gran"), to look after the tribe. In "The Serpent's Pass," a refugee goes into labor and Katara delivers the baby, claiming she did it lots of times, proving how much responsibility she had in her former home. Not only does she have experience delivering human babies, Katara claims to have delivered baby seals as well.
According to the unaired pilot episode included on the Avatar Complete Book 1 Collection DVD set, Katara's name was originally Kya, but was changed before the start of the series proper. In "The Tales of Ba Sing Se," Katara's name was written as 卡 塔 拉. Kǎ (卡) means to check, block, or card; Tǎ (塔) means pagoda; and Lā (拉) means to pull. The character Lā is the same La as the Ocean Spirit's name from the season one's finale, while the character for Kǎ also appears in Sokka's name.
In "The King of Omashu," Katara pretended to be Aang's granddaughter, under the alias "June Pippinpadelopxicopolis," in order to gain entry into the Earth Kingdom city of Omashu.
In "City of Walls and Secrets," Katara and Toph used false names to gain entrance to a party being held by the Earth King. Her name was Kuā Měi (姱 美), which translates to 'fascinating beauty.'
In "The Headband," during a parent/teacher conference, Katara played the role of "Mrs. Sapphire Fire", the heavily pregnant mother to Aang's Fire Nation cover-persona, "Kuzon", and wife to Sokka's "Mr. Wang Fire".
Book One
To Katara, waterbending is a unique skill that she dearly wanted to master. With no other Waterbenders to instruct her, Katara initially taught herself. Able to do feats ranging from maneuvering a fish-filled water globule to freezing water at will, she displayed much potential. However, she lacked a fine sense of control, unable to aim some of her larger attacks. After meeting Aang, she and Sokka set off on a journey to their sister tribe in the north, on a quest to find a Waterbending master to instruct them.
Katara continued to practice Waterbending diligently while journeying with Aang and Sokka, acquiring new skills. Passing through a port town, Katara stole a Waterbending scroll from pirates. Following the scroll's forms, Katara and Aang learned the "water whip," a maneuver that lashes a target with a whip-shaped formation of water. Later, while being fooled by Jet, she learned to bend underground water, as she and Aang pulled water up through geysers and into a river.
After Aang accidentally burned her hands while learning Firebending, Katara learned that she has a rare waterbending talent: the vitakinetic ability to heal wounds, using water as the catalyst.
When they finally arrive at the North Pole, Katara and Aang met Master Pakku, a Waterbending master. She hoped to learn Waterbending from him, but Pakku rebuffed her, explaining that tribal custom forbids women from learning Waterbending to fight. Instead, women with the gift are trained formally as Healers.
While Aang learns from Pakku, Katara is sent to the healing huts for Yagoda's lessons. After her lesson, she learned that her grandmother, Kanna, had been good friends with Yagoda as a young girl. However, she had fled to the Southern Tribe to escape an arranged marriage to a young Waterbender.
Filled with newfound contempt for Northern customs, Katara schemed to learn from Aang at night. Pakku quickly discovered them and banned Aang from further instruction until Katara apologized. Rather than submit to Pakku's sour chauvinism, Katara challenged Pakku to a duel. She acquitted herself remarkably and displayed how well she had progressed as a waterbender by demonstrating amazingly powerful techniques she had never used before during the fight. When Pakku sent a large stream of water towards Katara, she waterbended using her feet creating a sheeting of ice around her feet and ankles that secured her to the ground. She then vaporized the stream of water Pakku had projected towards her. She also created a frozen column of water and projected razor sharp discs of ice towards Pakku. At one point she collapsed two towering columns of ice jars over Pakku and though he countered her attack he commented that she was in fact an impressive waterbender. After this however, Pakku still did not consent to teach her, and he finally defeated her by imprisoning her in a cage made from spears of ice, hindering her movements. At this point Katara, though defeated, was able to hold her own against a Master Waterbender despite the fact a lot of her acquired skills had been self-learned (with the help of a waterbending scroll) over the course of a few months in which she had journeyed with Aang. This fact further indicated the great potential she possessed.
When he discovered Katara's heirloom choker, he recognized it as the betrothal necklace he had carved sixty years ago for his young fiancée, Kanna. Realizing that his stubborn adherence to custom had cost him a wife, Pakku consented to teach Aang and Katara. When Katara rose to mastery faster than any of his students, Pakku tasked her with instructing the slower-learning Aang and deemed her a master Waterbender.
In the Siege of the North Part 1, Katara is left to protect Aang while he journeyed into the Spirit World at the spirit oasis. Zuko breaks into the chamber. Katara duels him, and with the power of the moon, is able to temporarily defeat Zuko. Katara’s impressive combative skills even prompt Zuko to say she has been trained by a master. However, the sun rises and it enhances Zuko's powers, allowing him to defeat Katara. In the Siege of the North Part 2, Zuko carries Aang’s body to a cave. Upon Aang returning to his body from the Spirit World, Aang (restrained by rope) uses a gust of air to escape from Zuko by a few feet but didn't make it far. Just then, he is saved by the timely arrival of Katara, Sokka, and Princess Yue on Appa. Zuko and Katara have a rematch but due to the moon being out this time, Katara easily defeats him in a matter of seconds.
In the end of the episode, Master Pakku hints to Katara that she had mastered waterbending and would be able to instruct Aang when he left for the Southern Water Tribe.
Book Two
At the beginning of Book Two, the group is given by Master Pakku a box of Waterbending scrolls and an amulet full of water (with special properties) from the Spirit Oasis.
Master Pakku deems Katara a master Waterbender so she could officially teach Aang. Katara teaches Aang the Octopus Form in "The Cave of Two Lovers."
Katara saves the Waterbending scrolls in "Avatar Day" from a large Fire Nation man and, soon after, is able to put out fires on the parade floats with little available water. She uses the water from her water skin numerous times to cut through certain objects such as leather straps or wooden beams.
In "The Chase," she fares well against Ty Lee in a short confrontation by dodging her attacks, but Mai is able to defeat her by pinning her arms to a tree with shurikens; Katara, however, is saved by Appa in that scenario. When Azula tries to hurt Aang, she is prevented from doing so as her hand is grabbed by Katara's water whip. Katara offers to heal Iroh after his injury but is unable to proceed when Zuko refuses. In "The Library," Katara gives a Waterbending scroll to Wan Shi Tong, the knowledge spirit.
Katara has been shown able to create larger water whips, large whirlpools (with some help from Aang), and even small tidal waves. Her mastery over freezing water has also increased, ranging from small ice spikes, to small ice bridges, to surfing freely on water using an ice platform for support in The Serpent's Pass." She is also shown capable of rapidly condensing steam into ice in "The Drill." In the episode "The Earth King," she displays further mastery of Waterbending, being able to defeat many royal guards using a single aerial water whip kick after jumping over a moat. Furthermore, she can condense the water onto her arms (similar to when Aang collected rocks onto his arm against Azula in "The Drill") and use it as a limb extension in order to throw guards down into the moat.
Her advancing skills were further shown at the end of the second season finale "The Crossroads of Destiny" when she fought Azula in single combat and not only held her ground, but managed to drive Azula back. Despite Azula's powerful Firebending abilities, Katara was able to deflect the force of her attacks by covering her entire body except her head with water and then using the water on her arms as two enormous water whips, which she then uses to grab Azula's arm and leg to prevent her from Firebending. Azula's dire position was only relieved by timely aid from Zuko. The fact that she was able to best Azula signifies the extent of her combat prowess. It also shows that Katara has grown much stronger during Book 2, since in an earlier battle it took her, Aang, Iroh, Toph and Zuko to drive off Azula. As they leave the city on Appa's back, she attempts to heal the fatal wound on Aang's back with the water from the Spirit Oasis and, though the wound remains present, Aang does awaken soon thereafter.
Book Three
When Aang awakens from his near fatal injury, Katara takes him inside to have a healing session and, using her healing, she helps Aang see what happened to him in Old Ba Sing Se. While on the ship the group is attacked by another Fire Nation ship that discovered they had captured it, and a fight breaks out. Katara uses her Waterbending to separate the two ships, using a huge wave, and when she realizes they need to get away, she creates a huge steam barrier between them for cover, which was the first time she has manipulated steam, in the sense of directly creating it. Then, when they get hit by a harpoon, Katara uses her frosty breath of Waterbending to freeze the hole in the ship's hull, thus repairing it.
In The Painted Lady, Katara surreptitiously disguises herself as the river spirit, The Painted Lady, in order to help a helpless, polluted fishing village. She uses her Waterbending to run on water, shrouding herself in eerie mist, flitting about nightly, stealing food from the enemy and giving it to the village and healing the sick. With crashing waves and precise missiles of water, as well as help from Aang, who discovers her ploy, she goes on to destroy a huge factory, the source of pollution in the river. Later, as she invoked the wrath of the Fire Nation army encamped in the factory, she and the gang put on a tremendous display to scare off the antagonists. Katara, after creating a huge cloud of steam, dramatically destroys one of their river crafts by blasting it into the air on a mucky geyser and then shooting it into a nearby cliff. Also, throughout the episode the benders of the gang use their cumulative Earth and Waterbending abilities to purify the heavily polluted river water.
In the episode "The Puppetmaster," the group meets one of the last Southern Water Tribe Waterbender before Katara, Hama. She was kidnapped and thrown in a Fire Nation prison and tries to teach Katara the techniques of the Southern Water Tribe. First she teaches Katara how to pull water from the things around her therefore allowing Katara to bend practically anywhere. Katara is now able to do such feats as pulling moisture from the air and plants to waterbend. Hama also attempts to teach Katara the technique she used to escape the Fire Nation. It is the highest level technique amongst Waterbenders, but can only be utilized when the moon is at its fullest. It is the ability to control organisms by manipulating the water within them, a technique Hama calls "Bloodbending".
Hama attempts to teach it to Katara, but Katara having no desire to learn it states that she doesn't want that kind of power over people. Katara then found out that Hama was kidnapping Fire Nation civilians and then saw her as an enemy (not caring for Hama's justification that the civilians deserved it). With Katara quickly proving to be the stronger Waterbender, Hama tried to use Bloodbending to control Katara, but after using the full moon's energy, Katara is able to resist as her bending is more powerful than Hama's. It should be noted that Hama's waterbending is not necessarily weaker; a more logical explanation for Katara being stronger than a fully-trained master is that Hama has weakened in her old age. The two initiate an epic battle, with huge displays of Waterbending, as Katara, using her recent and nascent knowledge, and Hama both pull water from their surroundings. Katara triumphs, terrifying the momentarily defeated Puppetmaster. Immediately, Aang and Sokka show up, but they both fall victim to Hama. To put a stop to Hama's reign of terror, Katara was forced to utilize Bloodbending to stop Hama from controlling Aang and Sokka before they came to any harm.
Although she does not take much of a leading role as she usually does (Siege of the North & The Crossroads of Destiny), Katara's Waterbending was an important instrument over the course of the invasion in The Day of Black Sun. Katara and Aang share a kiss in this episode before he flies off to fight the Fire Lord. Katara eventually escapes with the gang on Appa heading for the Western Air Temple.
In "The Western Air Temple", the gang travel to the Western Air Temple for refuge after a sore defeat at the Fire Nation capital. Katara uses her healing abilities to heal the soles of Toph’s feet after she was accidentally burned by Zuko. The Combustion Man tracks the group down and attempts to ambush them while the group attended to Toph’s injuries, but he was thwarted by Zuko. Aang and Katara both use their respective bending elements to counter the Combustion Man’s attacks, but they are at an extreme disadvantage due to them being at a lower vantage point within the arrangement of cliffs. Katara used an incredible display of Waterbending by manipulating a massive wave from a fountain into the air towards the Combustion Man. From this wave, she created ice daggers and projected them at the Combustion Man, reminiscent of Katara's battle with Master Pakku when he trapped her within a cage of icicles in "The Waterbending Master".
