There was a young girl who was born into the water tribe. She was a waterbender, but that was on her mother's side. Her father's side were all firebenders. She did not know her father, as her mother died when they were young. She was tan like her mother, but bore the amber eyes of the fire nation. She does not know about her firebender lineage. She is a waterbender and a firebender, firebending is not in her knowledge yet. The opposite elements were in one person, but she someone managed to control both powers. She was raised with Katara, a waterbender as well, and Katara's brother, Sokka. They've been together since they were babies.
It has been for-told that Aang was not an only child. But that a young girl, a twin, was born with him. In the womb of their mother, the powerful spirit Ravaa didn't know which child to choose. They were both strong and determined. So she placed a small amount of her spirit in the girl and she put herself into the boy. The small spirit in the girl gave her the ability to bend all of the elements but the girl was never allowed to go into avatar state. When born the children grew up with each other a small time. Then Aang chose the toys of which the avatar chooses. And the young girl was sent back to her parents..... But what exactly happened to her? Did she ever meet her brother? Does she ever proceed her talents?
I only own Kyra and her children the other characters are owned by the makers of ATLA and TLOK.