close the borders
When King Primevil wishes to seal Garvidia, a giant wall of poisonous spikes appears before any character who comes within 100 feet of Garvidia’s borders. This wall extends from the ground up into the heavens. No amount of magic or muscle can move this wall. Upon touching the spikes, characters must make a fortitude save DC 25 or die. As soon as characters move beyond 100 feet from the borders of Garvidia, the wall of spikes disappears.