Magic was not originally meant to be wielded by humans. They did manage to learn how to channel it, but this happened all because of the War of Magic. When the Four Fiends wreaked havoc in Nihil and the Arkana, humans figured out they had a way of fighting back. The sheer will of not being exterminated was the main reason why magic was discovered. Not everyone was able to wield it, though. A select few learned about their affinity to that unseen force that soon started to be within their grasp.
One place in Uranos was rumored to contain the origin of Holy magic. This was the foundation of what became known as White magic. It was known as the Supreme Source. It was located next to the High Palace inside a vast chamber. Within this chamber, there appeared to be a sea of what seemed like magnificently crafted glass that shone in various colors. Just looking at it was an otherworldly experience in and of itself.