Repentance - p. 1 Dragon Age II Guide
Last update: 11 May 2016
The quest giver: automatically after completing the main quest The Deep Roads Expedition [Hightown - Viscount's Keep] or automatically after completing the DLC quest Duty [Hightown - Chantry]
Step 1: Talk to Sebastian
You can complete this quest only if you have the Exiled Prince DLC installed. Additionally you have to complete the DLC quest Duty first.
This quest can be activated in two ways. If you've completed the quest Duty in a first Act of the campaign, then you'll obtain this new mission right after getting to Act II, so after completing the main quest The Deep Roads Expedition and conversation with Viscount Marlowe Dumar in the [Hightown - Viscount's Keep] location. But if you've completed the quest Duty in a second Act of a campaign, then you'll obtain this new mission right after ending it, so after reporting back to Sebastian about killed mercenaries. Regardless of the previous events you have to travel to the [Hightown - Chantry] location during the day and talk to Sebastian, who can be found near the statue (M7, 5) #1. During a conversation #2 the prince will ask you to explore lady Harimann Estate (she is the one who sent mercenaries after him). Note that Sebastian has joined your party and if you want to go to the estate now, it is a good idea to find him a place in your active team.
Step 2: Explore lady Harimann Estate
You can now leave the Chantry and go to the estate district during the day. Find here the door (M3, 31) #1 leading to the [Hightown - Harimann Estate] location (M97, 1). Once you're inside, go up the stairs and head to the northern room #2 (M97, 2). You'll witness there first of several cut-scenes, which have one in common - people you see can't see Hawke or the rest of your party members.
Go back to the floor and use the southern door #1 leading to the dining room. You'll watch here a short scene too (M97, 3). Before you leave, look around the place and find a chest with an armor upgrade for Sebastian #2. You can also examine Lady Harimann journal which lies on the table.
You can now head towards eastern door. I suggest go to the east first. In the northern bedroom (M97, 4) you'll witness a quite funny scene #1 and also will find more pages from Lady Harimann's journal. Now you can go back to the fork and take a corridor leading south #2. You can check an eastern room on your way, where you'll find more pages from a journal.
Head south until you reach a basement entrance #1 (M97, 5). Go down the stairs. Once you're in the basement you can have a short conversation with characters which were ignoring you till now #2, but you'll be attacked by monsters soon (M97, 6).
After the battle begins, attack a desire demon #1, trying to kill him as fast as possible. When he is dead you can eliminate shades. After winning the battle examine demon's body and you'll find a valuable Fade's Fury dagger. Look around to find a nearby dead Flint Company mercenary #2 (M97, 7) because he possess an item which activates a new companion quest.
Unlocked companion quest: The Starkhaven Longbow