Piandao, modeled after Sifu Kisu, and named after a rare Chinese sword (a piandao (Ironically, this is not the type of sword he wields.)) is known to be the greatest swordmaster and swordmaker in Fire Nation history. He's also a master in the Order of the White Lotus, an "ancient secret society, a group that transcends the divisions of the four nations.." alongside Bumi, Fung, Iroh, Jeong Jeong, and Pakku, and he's a lover of the arts. He's not impressed by arrogance. He prefers that his students are humble and eager to learn.
You can read more about Master Piandao by visiting the Avatar Wiki. None of the Wiki's information has been confirmed by the series' creators, though. So I'm not sure if it's reliable. The info's good for fan fiction fodder, though, and who doesn't love fan fiction fodder? :)