This encounter can only happen if the Warden accepts A Change in Leadership quest. When they find Raelnor Hawkwind in the Denerim Market District they can choose either the option to kill him or side with him against his son, Taoran Hawkwind. Afterwards, when traveling from Denerim to a different location in Ferelden, this encounter will happen.
Taoran will be accompanied by eight Blackstone Irregulars (three of which are archers). If the Warden killed his father in Denerim before, they won't be able to initiate any kind of discussion with him. However, if the Warden sided with Raelnor they can initiate a fight with him and his men or intimidate him into paying 3 for not killing him (intimidation always works - no coercion skill required) or just walk away from the family business.
Notable items EditElfroot
The common name for canavaris, this herb actually has little to do with elves other than being commonly collected and traded to outsiders by the Dalish. It is the primary ingredient in many healing salves.
Use: Chewing elfroot restores a small amount of health, and those with skill can use elfroot to make more potent elixirs. x1