Arcanopause
From Delgar
The Arcanopause is a region of the world northwest of which there is no magic. It has defined a cultural boundary between the people of Dhol and the rest of the world for centuries. As one travels from south to north through the Arcanopause, magic gradually becomes less potent until it is completely gone by the time one reaches the other side. The islands within the Arcanopause are home to the Vargyr, who take Dhol children to be tested for magical potential at a young age. Those who possess an aptitude for magic (and are determined not to suffer from aethersickness) may be trained to join them.