Demon Marco AU. Tom returns into Star's life, but when Star starts to forget about Marco, he turns to the dark, and becomes a demon. But what happens when he awakens a greater evil? And can Star save Marco from The Demon Within him?
Star Vs. The Forces of Evil - Rated: T - English - Adventure - Chapters: 15 - Words: 69,087 - Reviews: 85 - Favs: 118 - Follows: 146 - Updated: 7/31/2017 - Published: 1/13/2017 - Star B., Marco D.