Dresden Files - The Archives
Estrella Knotley was a warlock who was supposedly killed by the Wardens of the White Council centuries ago for practicing black magics involving repeated violations of the 1st, 4th, 5th and 6th laws. Her apparent experiments in violating the 5th and 6th laws allowed her to escape her presumed death and travel across time to the modern area where she found shelter in the body of a young Frederick High student, and used her knowledge to guide into performing black magic while sticking to the shadows and nearly managing to pull off a giant ritual all over the city intent on using the chaos she had been sowing to power some kind of large temporal spell designed for an unknown (and now undeterminable) effect.
Estrella Knotley was cast out of her vessel and the spell’s major construct failed even if some of it’s more minor parts completed. Without Estrella’s guidance is it likely that the spells energy was wasted or directed in manners that she did not intend.
Young unpopular high-school student who was possessed by the Ghost of Estrella Knotley and began to lead her in black magic rituals while ensuring they would take the fall and not her if their actions were discovered.