Born in Zaofu, Yasuko had a rough childhood. Due to their financial situation, her parents forgot love, bickered constantly, and barely paid attention to their three children. While her father was a couch potato, her mother had worked 6-7 odd jobs to keep the family afloat. On the other hand, her brothers Yoshiro and Yoshito, who were twins, were eight years older than her, and they became her role models.
When their mother finally found another lover, the three children were left with their idealistic but lazy father, who had believed Republic City fostered "greener pastures." Thus, Yasuko, at the age of five, moved to the city slums.
Shortly after arriving in the city, the young earthbender discovered her capabilities. Hungry for a few fruits, the five-year-old was able to raise an earth column below a fruit crate and topple one apple onto her tiny hands. Luckily, she wasn't caught. Her earthbending brothers, who were quite proud of her abilities, then taught her their ways of forgery, pickpocketing, and other little evils.
Other pastimes of Yasuko was sports: basketball and archery. The latter sport, due to its costly demands, was harder to maintain; however, she had found an infertile old master willing to continue the Yuyan legacy.
One night, after a long day of archery practice, Yasuko found a redhead orphan counting his earnings in the city park. With their similar experiences and hobbies, the two quickly became friends. Dressed in her brothers' clothes, the female could pass off as another boy, which was her airbending friend assumed she was.
Unfortunately, their six-year friendship was tested when Yasuko's father, who was desperate for a better job than janitorial services, was recruited as a casino manager in Gaoling.
At first, losing her childhood friend seemed like losing the world; however, after a year or two, Yasuko was able to move on, find new friends, accept new lovers, and continue with life. In fact, where did she last place that action figure he gave her?
Moving into the Earth Republic once more, the children easily located patrons who can provide comfortable lifestyles. Employed by infamous gangs, the trio resorted to bloody jobs: head hunting, jewelry delivering, boss escorting, cactus juice dealing, and other whatnots. Their occupations had allowed Yoshiro, Yoshito, and Yasuko to travel around the Earth Republic and learn new skills from the locals.
Currently, Yasuko was given instructions to decapitate a traitor in Yu Dao. However, little does she know she'd be staying longer due to "unforeseen circumstances."