Yu

"earth"

- If you pay for the whole year in advance I'll bump you up to the next belt. Master Yu is an Earthbending master and a resident of the upper-class Earth Kingdom town of Gaoling. He is the manager and primary instructor of the town's Earthbending academy. He later becomes a bounty hunter, searching for Toph.

History
Yu was hired by Lao Bei Fong to train his daughter, Toph, in Earthbending. However, per Lao's instructions he only taught her basic moves. When receiving a free first lesson from the academy, Aang was beaten in seconds by a younger student rendering the lesson nearly worthless. Master Yu suggested that Aang pay for a year of lessons and that if he paid in advance, he would bump him up to the next belt. This suggested that he was more a businessman than true master, as this is a common practice among less-than-reputable martial arts schools. He along with Xin Fu was later hired by Lao Bei Fong to retrieve Toph.

In their search for Toph they reached Misty Palms Oasis at the edge of the Si Wong Desert. Master Yu appeared to be the more level headed of the two; he reminded Xin Fu (who mistook the bounty as dead or alive) that Lao Bei Fong wanted Toph alive. Xin Fu temporarily changed their target to the fugitives Zuko and Iroh to collect more bounty. Ignoring Master Yu's advice, Xin Fu directly confronted the fugitives but the White Lotus member Iroh was meeting with turned all the desperate men in the bar against them. Although outnumbered, Master Yu and Xin Fu dealt with them easily with their Earthbending skills, but in the confusion the Fire Nation fugitives escaped. They searched the whole town but to no avail, and finally returned to tracking Toph and the Avatar. They succeeded in capturing Toph in Ba Sing Se, luring her into a trap with a forged letter from her mother. After discovering Metalbending, Toph turned the tables, trapping Master Yu (along with Xin Fu) in the very metal box they had imprisoned her in. His fate after that is unknown.

Abilities
Master Yu is shown to be a proficient Earthbending master, and is well known in Gaoling for his abilities. He appears to prefer a more subtle, conservative approach to his Earthbending, as opposed to Xin Fu, who relies on brute strength. Instead of crushing people with large rocks, he will sink them into the ground, which requires much less effort.

Trivia

 * According to the leaflet from his school in The Blind Bandit, Master Yu's name is written as 余師傅 (yúshīfù). Yú (余) is a Chinese surname and 師傅 (shīfù) means 'master' which as a title is put at the end of a teacher's name.
 * Master Yu and his academy serve as a satirical parody of atypical "strip mall" dojos where parents are able to purchase belts for their children in disregard of the symbolism and substance behind them, as well as a reflection of the disdain Sifu Kisu and Bryan Konietzko have for the use of belt systems.
 * Master Yu has a very high interest in gold along with his partner, Xin Fu, that persuades him search for Toph.
 * Sab Shimono, the voice actor for Master Yu, is also the voice of Monk Gyatso.
 * Master Yu has a similar name to that of a notable figure in Chinese mythology. However, Yu the Great was a very persistent, hard-working, and determined man who eventually became the founder of the Xia Dynasty. In contrast, Master Yu is portrayed as a rather greedy and timid person, not worthy of the esteem connected to him. Therefore, it is fairly likely that the similarity of their name was either ironic or unintentional.