Living In The Shadows (Bill Cipher X Hoshimi Riyeko)

(this is a gravityfalls fanfictionso if you don't like gravityfalls then don't read it that simple)
Hoshimi Riyeko is a young half demon, she's exactly 1,400 pretty young for a demon I know. She lives alone in the forest in well not to make a big deal a mansion. She meets Dipper while in her shadow wolf form, which gave away who she was in a way. She later finds her self in a fight with a certain Dream Demon.