Su Jiang is a girl from the Fire Nation. As a girl, she was always fascinated with the spiritual side of Bending, and bothered by the Fire Nation's teachings on Firebending. Born to a middle class family, they saved up enough to send her to one of the prestigious military academies of the Nation, the only place one could study bending in any sense.
For years she suffered through the hours of combat instruction, finding she was pretty good at it, but preferring the more meditative side of the instruction (as thin as that is in current Fire Nation teachings.) To help, she also turned her attention to the healing arts.
When she reached the age of 12, though, the muttering started. After all, she had yet to so much as cause a flame to twitch. Her grades and performance were acceptable, but no bending would mean that she couldn't continue to attend. Perhaps frustrated with their promising student's proclivites as well, she was placed in a special class that would teach a more esoteric art.
Unbeknownst to her, she was actually being trained for what was perceived by a few nobles of the Nation as an inevitable coming war with the Earth Kingdom's warlord Chin. The Fire Lord ordered that there be no preparation, for fear that the Avatar might object to the creation of an army when there was no pressing need.
And then the war ended. Without a need for talented front-line soldiers, Su was quickly dismissed as a waste of resources and kicked out on the street. For a time she wandered, healing minor ailments for enough to survive walking from town to town through the recovering Fire Nation before she ran into a man with a bird mask...
