An Empyrea (plural: Empyreae), also known less formally as firmament, is a linear energy flow crisscrossing the Earth's surface. They originate at the core of the planet and radiate apparently indefinitely outwards. While not very measurable from the surface, in the atmosphere they are very noticeable, especially at their intersections. The largest known intersection is at Zephyros Wardos, in the Aeolian Mountains, and its energy is channeled by the Spires of Eternity.
Empyreae have many noticeable effects, mostly when high above the ground. At several of the intersections, they keep afloat massive chunks of stone, called Empyrean Islands, which have been long undisturbed by men and mages, and are the nesting grounds of the Avyn. Airship captains often try to fly on these lines, as they make their magical engines more efficient and thus faster. Primordials use them for travel, since they work to conduct their energy, though this is a rare occurrence (primordials rarely leave their native land). Magic users also notice slight increases in energy on these lines.