They Have a Sister(Spn Fanfic)

(This is an SPN Fanfiction). Isabelle is the little sister of Dean and Sam Winchester. Yeah um what? You heard me. The menacing Winchesters have a little sister that they will protect and fight for until they die, or the earth ends, but that's already happened. She can take good care I herself and is a vicious bitch most of the time, but she has a soft spot for family. Honestly, she loves the thrill of hunting and saving people from a messy death. Banishing spirits and fighting demons. My name is Isabelle Winchester. The story books may have forgotten about me but the paranormal tremble at the name Winchester. The look of surprise when a supernatural being looks at me and realized that I, too am a Winchester make me smile. Watch out creatures. Because my brothers and I are coming for you