Hong Shen is an actor and firebender from the Fire Nation colonies, and the father of Hong Zhen. He leads a double life as a folk hero known as the Red Spirit, robbing the Fire Nation military in order to help the poor. After a run-in with Zuko, he gave the banished prince a set of dual broadswords and ultimately inspired him to take up his own alter-ego as the Blue Spirit.
After his banishment, Zuko began a trek of the air temples to look for clues to the location of the Avatar. Heading toward the Eastern Air Temple, Zuko stopped at the Fire Nation port at Ye Niu Bay in the former Air Nomad territories to procure supplies and maps of the surrounding area. However, his request denied by the colony's overseer, Commander Kanku who was afraid of losing favor with the Fire Lord. Returning to his ship, Zuko encountered a thief in a red mask looting his storage; however, the thief escaped. He later learned that this thief was a local folk hero known as the Red Spirit, who had been robbing robbing the military for several months and giving the goods to the poor.
Later, attending the local Fire Festival, Zuko witnessed a performance where an actor dressed as the mythical Monkey King Sun Wukong fought and defeated Earth King and conquers Ba Sing Se. Zuko recognized the actor, whose name was Hong Shen, to be the Red Spirit and confronted him. Hong, who was in fact a talented firebender, admitted to stealing, but defended himself by saying that Commander Kanku had been unjustly stealing supplies from the villagers. Shen agreed to help Zuko steal the maps if he would assist him with another task and gave him the Blue Spirit mask as a disguise. After successfully stealing the supplies and map, it was revealed that Kanku was keeping Shen's son Zhen as a hostage in order to coerce him to enlist in the military. When Zuko was confronted by this cruelty, he became emotionally distraught, and after hearing Shen condemn the Fire Lord, he nearly attacked the two; however, he restrained himself and flew into the forest instead. He later found that Shen had left him his broadswords as a parting gift.
- Shen's disguise as the Red Spirit is a pun on his name. Though Hong ( , "flood") is a common surname in China, and Shen can be written with a number of characters, his name can also be written as , literally meaning "Red Spirit".
- Sun Wukong ( ), commonly known as the Monkey King, is a famous character from traditional Chinese literature, first appearing in the classical novel Journey to the West.
- Despite the fact that he gives Zuko his dual dao swords, they are not the same swords he used as the Red Spirit. Zuko's swords share a single sheath, while Shen's swords have their own individual sheaths.