Repentance - p. 2 Dragon Age II Guide
Last update: 11 May 2016
You can now leave the basement (M97, 8) #1 and get to the [Underground passage] locations (M98, 1). Head east. You'll run into a first group of monsters after going down the stairs. Try to eliminate shades first and then kill rage demon #2. You should use items which increase your immunity to fire element of course.
Continue east. Expect a second hostile encounter after you reach a large hall #1 (M98, 2). At the beginning you have to fight only a revenant so it is a good idea to retreat to the previous location and wait for a demon. When it is dead, enter the same large hall. Now you have to deal with corpses and skeleton archers #2, but it shouldn't be a big problem.
Look around and then choose a passage leading to the north #1. When you reach a larger fork (M98, 3), a new group of monsters will attack you. Try to kill skeleton archers first and then face two rage demons #2. After eliminating them, first attack shades and corpses afterwards.
Head west now and then turn to the north. You'll run into another group of monsters (M98, 4) - focus on eliminating revenant first #1. After it is dead, attack corpses and skeleton warriors but watch out for an arcane horror which will appear after a while #2. Once you've see it try to kill it fast preventing it from casting powerful spells.
You can use a northern passage now #1. After few moments you'll reach a last room in this underground structure #2. I definitely suggest saving your game here, because a conversation scene will start in a few moments. You'll meet Lady Harimann and Allure, a desire demon (M98, 5).
Step 3: Meet Lady Harimann and Allure
You can choose several dialog options during this conversation #1, but its result will be the same. The only difference between them is how many points (friendship or rivalry) with party members you'll get. When the conversation ends the battle will start #2.
I strongly recommend starting with attacking Lady Harimann #1. You should kill her fast and that's because she is a mage. Then eliminate Allure #2 - she is able to support other monsters. Afterwards attack shades, which shouldn't be a big deal even if there are many of them. After winning the battle examine Allure's body - you'll get Allure's Crook among other items.
Step 4: Return to the Chantry
You can now use a passage nearby #1 (M98, 6). You'll return to the [Hightown - Harimann Estate] location (M97, 8). One more short conversation awaits you in the basement #2. It is worth noting that if you choose upper right dialog option you'll get 5 friendship points with Sebastian, while middle right or bottom right dialog option will give you 5 rivalry points with him.
You should go through the entire estate now, reaching a door leading to the [Hightown] location (M97, 1). Head to the Chantry. After reaching the [Hightown - Chantry] location, click on Sebastian #1 (M7, 5). Note that during this conversation you'll be able to advise the prince how he should behave or to flirt with this character #2. Depending on the dialog options you choose you'll gain 10 friendship points or 10 rivalry points with Sebastian. All options result with 11 sovereigns of reward.