Piandao

History
The greatest sword master and sword maker in Fire Nation history, Piandao was born to two Firebenders. Ashamed that their only son wasn't a bender, his parents left him on the doorsteps of an orphanage. Growing up, Piandao was a nervous and agitated child, but he showed interest in the arts and enjoyed painting and calligraphy. It helped him relax and focus his mind. At the age of 10, Piandao attended Fire Nation boys' camp where his natural talent with the sword was recognized. He furthered his studies in the army, where he developed a vicious and fearsome sword fighting style. Piandao fought many battles for the Fire Nation and won them all. But after several years of fighting, Piandao lost his taste for war and wanted to become a more enlightened person. So he left the army and traveled the world for many years, studying under a variety of benders, warriors, and artisans. He then returned to the Fire Nation and settled in the town of Shu Jing. One day, the Fire Nation army came to arrest him for deserting the army. In a legendary battle, Piandao defeated all one hundred soldiers and the army has never bothered him again. (nick.com)

After Sokka figures out he does not openly contribute to the group, he seeks out Piandao. Sokka then traveles to Piandao's palace. During the interview, Sokka humbly admits his own unworthiness to the master, which is exactly what he was looking for. He decides to take Sokka under his wing. He is set about to do tasks such as landscape painting and calligraphy, as well as practicing against one of the master's underlings. Piandao believes him to be worthy enough to choose a steel to make his sword. Sokka makes a sword out of a meteorite. When Piandao gives Sokka the sword, Sokka refuses, though, and confesses the truth about actually being from the Southern Water Tribe. The master attacks him, and they then engage in a duel. As the duel between Sokka and his master moves outside, Sokka uses the techniques he's learned--coupled with his youth and agility--to get the upper hand (something the master points out several times) However, the swordsmaster finally gains the upper hand, but sheaths his sword before delivering the final blow. He now reveals that he had known Sokka was from the Water Tribe all along just from his name, and also notes that Aang is the Avatar. Nonetheless, he claims that the art of the sword does not belong to any one nation, and gives Sokka his sword back.

When the group leaves, they are given a bag with Pai Sho peices, one of them being a White Lotus. As the doors to the master's home close, they notice that the symbol of the White Lotus can be seen surrounding that of the Fire Nation.