Avatar: Every Master Aang Learned Bending From In The Last Airbender
Aang learned the four bending elements from many different masters in Avatar: The Last Airbender, and had some extra skills to learn as well.
Aang's journey to becoming the Avatar wasn't one that he travelled alone in Avatar: The Last Airbender. The young hero had to learn all four types of elemental bending - and other arts - from many different masters along the way.
Usually an Avatar's training is carefully guided along a set path, with different masters from each of the disciplines assigned to the newest Avatar in turn. However, Aang's Avatar training was thrown off-course when he was frozen inside an iceberg for a hundred years, and had to find masters for himself by roaming the Four Nations with his newfound friends, Katara and Sokka. While some of his learning was traditional, like his time spent with the Northern Water Tribe's Master Pakku, Aang also learned bending from some unusual teachers.
Each of Avatar: The Last Airbender's three seasons focused on a different nation, with Aang journeying to the Northern Water Tribe in Book 1, exploring the Earth Kingdom in Book 2, and finally facing the dangers of the Fire Nation in Book 3. Here are all the teachers that he learned from along the way.
Aang's first teacher was Monk Gyatso of the Southern Air Temple, who was as much a friend as he was a teacher, and the closest thing that Aang had to a father growing up. Aang was taken away from his real parents as a baby and put on a path towards becoming the Avatar before he even knew that was his destiny. Monk Gyatso had also trained Aang's predecessor, Avatar Roku, so the young boy was already an old friend to him. Unfortunately, Aang's close attachment to Gyatso led to disaster when he learned that he was going to be sent away to the other nations to learn from different masters, in anticipation of a coming war with the Fire Nation. To avoid being sent away, Aang fled the Southern Air Temple and ended up frozen inside an iceberg. Monk Gyatso died in the ensuing attack on the Southern Air Temple and his skeleton was found surrounded by the bodies of Fire Nation soldiers, indicating that he went down fighting.
Katara's waterbending was responsible for freeing Aang from the iceberg, as she cracked it open and released him and Appa from inside it. As the last waterbender of the Southern Water Tribe, Katara had to teach herself waterbending and was not very advanced when she and Aang first met. She taught him the first few basic moves that she had learned, and was jealous when Aang mastered them quickly and with ease. They acquired a waterbending scroll with other techniques that they could both learn, but it wasn't until they reached the Northern Water Tribe that Aang was finally able to learn from a master: Pakku. This curmudgeonly teacher initially refused to train Katara, insisting that she only be taught the art of healing along with other women of the Northern Water Tribe. Katara duelled Pakku for her right to train with him, and he ultimately relented when he realized that she was the granddaughter of his long-lost love, Kanna. Pakku trained both Katara and Aang, but while the young Avatar became a competent waterbender, Katara ended up surpassing him in skill.
Aang was fortunate enough to learn the art of earthbending from the greatest earthbender who ever lived: Toph Beifong. Fighting in underground bending matches under the pseudonym of The Blind Bandit, Toph was actually the daughter of a nobleman who had tried to force her into a sheltered life - which Toph had no interest in. Toph herself had learned earthbending directly from the original animal masters, the badgermoles, who were blind like her. She had a unique mastery of the art that included special abilities such as seismic sense, which allowed her to see her surroundings and feel the approach of enemies from far away, and "truth-seeing," which allowed her to tell whether or not a person was lying by listening to their heartbeat. Toph was also the first to discover metalbending, a special form of earthbending that allows the practitioner to manipulate the earth in its purified and refined form: metal. Aang was fortunate to have such a skilled teacher, though he initially struggled to master earthbending and Toph was not particularly patient with him.
Aang's pursuit of firebending ended up being the most fraught of all his learning paths, and for a long time after his disastrous first attempt he was afraid to even attempt it again. Aang initially sought to learn firebending in Avatar: The Last Airbender season 1 from the firebending master Jeong Jeong, a member of the White Lotus. Jeong Jeong took a cautious approach to teaching Aang that was focused on discipline, but Aang's impatience led him to try firebending unsupervised, resulting in him accidentally burning Katara. After that Aang was reluctant to learn firebending and didn't return to it until Avatar season 3, as the time when he would have to face Fire Lord Ozai drew close. Zuko attempted to teach Aang what he knew, only to discover that his own firebending abilities were greatly weakened after defecting to Team Avatar. Together, Aang and Zuko travelled to the Sun Warrior ruins and learned the art of firebending from the original masters: the dragons Ran and Shaw.
The Avatar State is a powerful but dangerous state of being that Aang can enter into, in which he wields all four elements simultaneously with the power and skill of every Avatar who has come before him. Aang was able to the enter the Avatar State instinctively but had little control of it, which is particularly dangerous since killing the Avatar while they are in the Avatar State will end their cycle of reincarnation and bring the line of Avatars to an end. In Avatar: The Last Airbender season 2, Aang met a very old man called Guru Pathik at the Eastern Air Temple. Pathik offered to teach Aang how to unlock each of his chakras so that he could deliberately access and control the Avatar State. The training went well enough until the time came to unlock Aang's seventh and final chakra, and Pathik told him that he would have to let go of his feelings for Katara. Aang wasn't prepared to do this, and abandoned his lessons when he sensed that Katara was in danger, leaving Pathik to go and rescue her. This risked locking his seventh chakra permanently, but fortunately Aang was still able to enter the Avatar State later on.
The final skill that Aang learned was also the most rare. Torn over the prospect of being forced to kill Fire Lord Ozai, Aang ended up finding an alternative solution from a very unusual place: an ancient, gargantuan being called a lion turtle. As revealed in The Legend of Korra, it was the lion turtles who originally gifted humans with the ability to bend the elements, and they have the ability to both grant bending powers and take them away. After Aang asked the lion turtle for advice, it granted him the ability to energybend, through which he could take away a person's bending abilities. As far as Avatar canon has revealed, Aang used this ability only twice: to stop Fire Lord Ozai from destroying the Earth Kingdom, and to strip a dangerous bloodbender called Yakone of his bending powers.