The primary route connecting Argysis to Hephake and the lowlands beyond, a narrow defile cutting between towering peaks. A series of toll-gates and checkpoints line the passage, their stonework predating the dragon conquest by centuries.
Under Rothogomos, the passage is technically open but heavily surveilled. No dwarves man it; none are left in Argysis to. The checkpoints are held by Shyka garrisons, the dragon's bred servants, who report straight to Othyndria. Tariffs are high, searches are invasive, and certain goods are forbidden outright: weapons, maps, anything written.
Smugglers use alternate routes: the goblin-controlled tunnels through Gymlstik (expensive but reliable) or the treacherous high passes where weather kills more travelers than bandits. Hephakean merchants grudgingly accept the official route's costs as the price of maintaining trade with their lost cousins.
The passage is also the most likely invasion corridor if Hephake ever decides to "liberate" Argysis—or if Rothogomos decides to expand south. Both possibilities keep the checkpoint garrisons alert and the fortifications maintained.