Isabelle lightwood x villain reader

Y/n, Isabelle, Alec and Jace were the best of friends when there was little, while Isabel, Alec and Jace got powers from the runes y/n didn't she had her own powers she could turn into a shadow and hide in them not even a shadowhunter could see her. People always called her shadow but she didn't mind but then she met the rouge. He used his magic to put her under his spell. Y/n left the institute and became a villain she would steal anything she could get her hands on. the shadowhunters had no over choice but to try and bring her in. Then they realised........