Population Migration / Travel
The civil war causes the Gerudo Desert to receive people fleeing Hyrule. The eight, the Gerudo leaders, take them in and allow them to live in Gerudo canyon.
Being on less than favorable terms with Hyrule (they often supplied the rebels of the civil war), the Gerudo have a safe place for refugees to flee to. The eight, the Gerudo leaders, take all those fleeing the war and allow them to live in Gerudo canyon. One such person was Magnus. However, he was clearly being hunted by the Hyrulean military, which prompted a series of attacks. The Gerudo agreed to continue to hide him on the promise that he would teach them magics and eventually bring peace between Gerudo and Hyrule.