Way to unlock: Meet with Leliana.
The quest-giver: Leliana (M2,3)
This quest becomes available after you complete your first journey to Val Royeaux, which takes place during The Threat Remains main quest. After you return to Haven (M2,3), a meeting will be summoned to discuss the situation with the Templars and the rebel mages. During the meeting, Leliana mentions the Grey Wardens and reveals that ward Blackwall has recently been seen in the Hinterlands.
You can now travel to Hinterlands. Head towards the lake in the central part of the map (M3,14a). Here, you find Blackwall accompanied by a group of recruits. Try to talk to the warden, which will result in several bandits arriving at the scene. After you start fighting, focus on eliminating the archers quickly, and then deal with the enemy fighters.
After you win the battle, you can talk to Blackwall again. As usually, the most important is the final part of the meeting, where you can offer him to join you, or dismiss him. Of course, I recommend that you o the former, especially that Blackwall is a perfect warrior.
Rewards for completing the quest:
- New Ally: Blackwall
- Experience (few)
- 80 Influence points
- 1 Power point