After her parents were murdered when she was fifteen, she ran away to escape her would-be captors. She made her way through England and up to Dumfries, Scotland, where she lived a secluded life to hone her abilities. After four years, she made her way back to London when she received word that Ciel Phantomhive was alive and well. This put her on the map of the people hunting her, but it was time to face her past. It was time for her to have her revenge, and in doing so, she discovered more than she bargained for.
Black Butler does not belong to me; therefore, the characters of Ciel Phantomhive, Sebastian Michaelis, Mey-Rin, Finny, and Baldroy as well as the plot from the anime are not mine and belong to the creators of Black Butler. However, Sebastian's character development and the character of Thalia Byron as well as what happens with the Olympians (other than their descriptions, which belong to Rick Riordan) are creations of my own imagination and belong to me.