Percy Jackson and the Olympians: Legends

The Hearth of the Gods sits in the center of the Hall of the Gods and is tended to by Hestia. The hearth in the throne room of the gods is a magical flame that glows brighter when the gods are at their strongest. However, it is shown to get colder and harder to keep alive when enemies approach (such as the Titans) or when the gods are weakened. If Olympus is ever attacked or worse, conquered by enemy forces, the flame of the hearth will die. In this event, Olympus would no longer be considered the home of the gods and may be lost forever, preventing the gods from moving on. Even if the flame of the hearth goes out, Hestia, being the 'last Olympian', would still exist in other hearths, as she is not tied to the hearth on Olympus in the same way that the other Olympians are tied to their thrones. Despite its enticing glow, the flame was lethal to anyone who touched it, both Mortal and God alike.