Sans au x Magic!reader

One day y/n fell down a hole in Mt.Ebbot while sleep walking. She woke up and was not surprised that she had no wounds. She walked around and continued on her journey. Ink later finds the au she was in. He had never seen it before so him and some other sanses explored it. It had the same people from undertale but what they didn't know was that there was a person that knew about gaster that also had magical abilities. Y/n knew undertale gaster cause her and original sans were siblings and his family was the only one who knew about her powers. Y/n had known about aus cause gaster told her about them.
She remembered the name of every sans cause she would read books about them. She knows wing dings. Her left eye glow (f/c). She has angel wings that nobody knows about. She also can imagine things and make them become real. She also has 3 forms. They are human,error, and skeleton. Her true form was skeleton.(I am just going to say y/n said in wing dings cause I forgot how you spell words in it) (Please don't judge this is my first story. Also feel free to comment ideas or questions for me)