Xin Fu was the promoter as well as the host of the underground Earthbending tournament Earth Rumble VI. However, he and Master Yu were later given the task of recovering Toph by Lao Bei Fong, Toph's father, and Xin Fu thus became a bounty hunter.
The promoter as well as the host and referee of the underground Earthbending tournament Earth Rumble VI, Xin Fu seems on the outside a nice enough person, but when prompted with the possibility that he has been cheated, his more underhanded side becomes clear. He kidnapped Aang and Toph when The Boulder suggested that Toph purposely lost the match to Aang, and then split the money with him afterward. Though Xin Fu is seemingly a powerful Earthbender since he lasts longest against Toph, he is still defeated. He is then recruited by Toph's father to retrieve Toph who Aang "kidnapped" by "any means necessary", and is now pursuing Aang, Katara, Sokka, and Toph alongside Master Yu. He has also shown that if he catches Aang, he fully intends to sell him to the Fire Nation for a large monetary reward. He is shown in "The Blind Bandit" to be a proficient and powerful Earthbender as he was once an active competitor of the Rumble. In fact, Xin Fu has shown himself as a stubborn and greedy earthbender who will do anything for money.
In "The Desert," it is clear that Xin Fu mistook the bounty on Toph for being a dead-or-alive bounty, but was quickly corrected by Master Yu, stating "No she's not, I'm certain he wants his daughter alive..." They temporarily change their targets when they spot the fugitives Zuko and Iroh entering a bar. Master Yu insisted on patience to wait for the right moment, but Xin Fu's impulsiveness gets the better of him and tries to arrest them, but the White Lotus member turned the whole bar against them. Xin Fu and Master Yu beat all the men in the bar, but in the confusion the fugitives slipped away. They search the whole town but with no success, thus changing their target back to Toph. In "The Earth King", they finally manage to catch her by luring her into a trap with a falsified letter from her mother. Xin Fu claims to be the greatest earthbender in the world, not Toph. At least, thats what he thinks. In "The Guru", Xin Fu is captured by Toph in the very metal box he imprisoned her in. He is not heard of again for the rest of the series.
- Xin Fu appears in "The Blind Bandit", "The Desert", "The Earth King", and "The Guru." Although partly obscured, his name in Toph's ransom letter was written as 辛富 (xīn fù) which translated as 'bitter rich.'