It's not actually illegal to be a wild mage.
Terec reminds himself of this, often.
Nor is it illegal to go north.
He reminds himself of that, too.
Terec was born with a wild talent for fire, and can no longer suppress it. Soon he will not be able to hide it, and he fears it will burn out of control, no longer singeing his bed-linens but hurting those he loves.
If you head south from his family's lands, you go to Astandalas of the emperors, heart of the empire, rich with magic. You go seeking fame and fortune and adventure.
If, on the other hand, you head north, towards the edge of the Empire, the edge of the known world, the edge of the Wild ... well. You might find adventure, but you won't be looking for it.