Way to unlock: Talk to Blackwall at Skyhold (the first conversation with this character in this location - requires a female!).
Quest giver: Blackwall (M12,18)
As soon as you reach Skyhold, you can start a love affair with Blackwall (if your character is a female and you have already flirted with Blackwall). If you want agree, after the conversation, in which you should pick the replies marked with the heart icon, you will be asked for a favor. Now, find him in the stables and talk to him to receive the quest. Now, go to the Storm Coast. There, reach the marked hill and find Blackwall's badge. After the conversation, you end the quest. After you return to Skyhold, you will witness a scene between your character and the ally, during which you can confirm your will to enter a relationship.
Rewards for completing the quest:
- The option to start a relationship with Blackwall