you were a Fatui Herald...you joined Capitano, you were his apprentice but during the war against Celestia your Pyro powers were unleashed, revealing that you were one of Celestia's daughters...you lost control, you went crazy, you burned everything

even yourself, you turned into dust...Il Capitano felt destroyed, he had never told you but he was in love with you during the 200 years they spent together...now he hoped that as a goddess you would be reborn