I remember that she dies and gets reincarnated as a baby. There's also a scene where she sees all the element spirits in front of her and I think she was in a crib? They go to visit their father's brother or friend and she goes to the training grounds with her brother and there's a kid there.

I also remember that on the cover, there is a little girl with black hair? And there're element spirits flying around her and she's outside.