In the konoha village , once there attacked the kyuubi .And the fourth hokage and his wife sealed it inside his wife and his child Naruto .
The fourth had a twin son and daughter (which was yuna uzumaki) . The son had kyuubi sealed inside him while girl was just weak and didnt inherit anything from namikaze and uzumaki blood . He lost interest in her and ignored her while his wife also did the same because she was useless.
when she was 2 she realized that her family didnt care about her .If she woke up late then they would just ignore her and she wouldnt even have anything to eat . inorder to eat she would look for food inside the forest and eat it .And if she got home late The doors would be closed and nobody would let her in . She would have to sleep outside time after time .Then time passed and she became 3 years of age , she also realized that they wouldnt celebrate her birthday rather instead of twins birthday it would be just naruto's birthday . She felt like she was a ghost infront of their eyes. A ghost that doesnt exist , doesnt hold anything to them . She was sad as tears ran out of her eyes when she saw her parents celebrating naruto birthday while the doors of the house were locked and she was outside of the house laying down crying.It didnt took long for her to cast aside her emotions for her parents . She ran towards the hokage face monuments and sat down on 1st hokage face and started crying and wishing for power so that she can live in this accursed world .' Please i dont care about my family anymore i dont care about the people in this world anymore .Please!!!!Give me power to Destroy my fate. If there is a god out there please help me please!! "cries" .' she yelled inside her mind while a cloud started forming in konoha and and lightning struck her .
"HaHaHa!! How foolish of me to think i would be this naive . " she said as she closed her eyes and saw herself infront of her.
"Hello there i am another part of you . i am sorry that you had to suffer instead of me . Say you wanted power ? i will give you power .you wanted to be stronger than your brother? i will make you the strongest in this world . We are one and will live as one . We will become one and you will gain my memories and i will gain yours " she said as she hugged yuna ( which was the part that didnt have her previous life memories).
She opened her eyes as she found herself in konoha the village hidden under leaves. She was happy amd at the same time sad to see the world around her . She wanted to see the gentleness of her parents (that are in naruto world) but due to plot change minato and kushina became scum who only cared about things that will benefut them . As of this day with her memories coming back she vowed to become the strongest.