He was supposed to be a good friend of Rohen and the chances were very likely that Rohen paid him a visit before his departure.
Sartarius then gave the rune warrior a writ of passage. By using it the portal guards let her pass and enter the portal to Liannon.
On Liannon the rune warrior found herself on a small path leading to the village. Within the village Darius stands in the very center and hardly cannot be missed.
When asking him about Rohen he said he really was here but already traveled on further to get to the Wildlands.