Although the Tower of Dusk was established in Doland, and only had influence over Doland and a few surrounding regions, their business network had long stretched outside the Breezy Plains.
That opponent hidden behind the scenes might be able to prevent the Tower of Dusk from selling any potion or any weapon, and from acquiring any piece of herb or ore in the Breezy Plains, but wouldn't have the ability to do anything outside the Breezy Plains. They wouldn't be able to control the royal office of Felan and Ledin, or influence the two great shrines in any way. If they had that ability, they wouldn't have to fear the rise of the Tower of Dusk.