Little Birdie [DS/KNY X FEM!READER]

[Y/N] Rengoku, little sister to Kyojuro Rengoku, is on her way to becoming a hashira - just like her beloved slightly older brother. One difference between the two though: [Y/N] doesn't use flame breathing like Kyojuro does. She uses a technique known as bird breathing. Will she witness her dream of becoming a hashira coming true, or will she give up halfway? Or, even bigger question, will she survive?