"The energy that flows through the Ray Streams beneath Fulheim. Ray is a fundamental resource for those living on this world, used in city lights to Lightship engines. Access to Ray greatly affects a nation's power."
Ray is a source of energy that flows throughout the world of Fulheim. Using the right technology, Ray can be extracted and harnessed for use as a power source. Most technology in the Arc Rise Fantasia universe is powered by Ray, including everything from city lights to lightships.