6 years ago twilight died in a explosion and rainbow was in love with her at the time. As dash held twilight's dead body in her arms crying a demon showed up and offered her a deal to change places with twilight. She agrees and the demon used a tiny bit of time travel magic unique to her the demon named watch blood. after rainbow dies she will be resurrected as demon and be loyal to hell for all eternity. Now she goes by shadow dash and is one of hell's best dealers and collectors. She then finds some info about twilights death and plans to enact revenge on those responsible and make sure her friends stay safe so they don't get hurt again.