The Flame of Olympus is Emily Jacobs, or Riza later on also , the main protagonist of the series. Being the flame, it gives her the "Heart of the fire". She also has Fire powers, Very much shown in the second book. In the third book, the Flame is shown to have a mysterious power to teleport people and/or objects to a mysterious planet in the Solar System. In the fourth book, after traveling to this mysterious planet and finding that it is the home of the powerful Xan, it is revealed the Flame is actually a fragment of the last Xan , Riza, who resides within Emily. They then embark on a journey with a CRU agent , Joel