A world of swords and magic, Atreia is actually two separate worlds, or rather two pieces of a world that was destroyed by a cataclysm. People live on the inside of what was once a hollow planet. Since the sphere shattered, humans of both halves have evolved to be physically different. In between the opposing forces is a space called the Abyss, which is home to the world's former masters (and now banished demons), the Balaur. The lore is too vast to relate here, but the important part is that both factions fight against each other and against the Balaur.