Kiyi was born to Ikem and Ursa, who went through life as Noren and Noriko respectively after having their faces changed by the Mother of Faces.
When Noren invited Team Avatar into his family's house in 102 AG, Kiyi decided to talk to Zuko and Azula, who were, unbeknownst to either of them, actually her half-siblings. She asked them if they wanted to see her doll, a suggestion Azula bluntly refused and Zuko happily accepted. Kiyi told him that the toy was also named Kiyi as she thought it was "such a good name". When Zuko commented on the doll's haircut, Kiyi told him that she had tried to make the doll prettier, but she had accidentally cut too much of its hair off. Zuko responded that Azula used to do things like that to her own dolls as a little girl, however Azula clarified that it was not the hair of her dolls that she cut off, but rather their heads, and asked Kiyi if she wanted a demonstration. Scared, Kiyi shouted "No!" and went back to her parents. When Team Avatar left Kiyi's family's house, Kiyi begged Zuko to come back some time.
Kiyi met Zuko again when he returned some time after, claiming her mother to be Ursa. Confused, she hugged her mother, though was passed on to her father. Before she could make sense of the situation, however, Azula, intent on killing Ursa, barged into the family's home through the roof. As the princess fought with Zuko, Kiyi was taken to safety by her father. Later, Kiyi and her father sat at a campfire, preparing a meal while her mother, who had regained her old face and memories, began talking about her past with Zuko. Afterward, she accompanied her parents when they visited the capital for the first time since Ursa's exile.