The Deep Roads Expedition is arguably the longest quest in Dragon Age 2. Players will explore the dwarven-built underground tunnels in search of treasure, and battle many new enemies, including dragons, darkspawn, golems and much more. The quest is siginficant for ending with arguably the game's hardest boss fight against an Ancient Rock Wraith.

1. Once you've completed all the prerequisites for this quest (50 gold and the underground maps from the Tranquility quest), you will be ready to start.
2. Speak with the dwarf (Bartrand) in Hightown's dwarven quarter, near the merchant area.
3. You can now leave on the Expedition, thus completing the first and longest part of the game. If you want to, take some time to once again sell any stuff you have, or even purchase anything you want. When you’re ready, speak with Bartrand again.
   
4. Note: If you take Bethany to the expedition it is likely that she will die, depending on your main character gender and class.
   
5. Note: It is HIGHLY suggested to take 2 healing mages to the Deep Roads, as they will make a specific boss fight much, much easier. This usually means Anders and Bethany, depending on how you specialized your characters.
6. After the cutscene, agree or refuse to help the Dwarf by looking for his son, and set out towards the quest arrow.
7. You will fight some Darkspawn enemies here. Just keep in mind that it is easier to first let them all come to you, so that you can effectively AOE a lot of them.
   
8. After you find the boy, continue moving through the passages.
   
9. The Dragon fight is the first real challenge in the Deep Roads. Make sure to spread out your melee attackers so that they are not all getting hit by the flame, AOE down the dragonlings that run in, and, most importantly, Taunt off your Tank with your other character if possible, to prevent the Tank from dying. Potions are also incredibly useful here. You may also decide to pause the fight a few times, and issue some specific commands to your party members that may be useful (for instance, some single-target abilities that deal damage or weaken the dragon’s attack, as well as simply moving  a specific party member out of harm's way).
   
10. Explore the cave after the cutscene.
    
11. Kill the Shades before you focus down the Golem, because it has a lot of hit points.
    
12. You will have to find another way out after Bartrand locks you in. Make your way through the door behind the Altar.
    
13. Make sure to quickly focus down the Shades with AOE, as they die quickly but can deal significant damage.
    
14. Decide on whatever you want to do with the Profane Leader’s offer. The easiest solution however, as usual, is to agree.
    
15. The Rock Wraith fight provides some new mechanics, and is one of the hardest fights in the game. Start off by spreading out your melee attackers just as with the Dragon, since the Wraith has a cleaving attack.
    
16. When the Rock Wraith compacts itself into a ball of rock, quickly hide with your entire group behind the pillars by issuing the Hold command by pressing H, and then right clicking your whole group behind a pillar while paused. Don’t forget to turn the Hold off by pressing H again, after the AOE is complete. Repeat this any time the Rock Wraith casts this spell.
    
17.  Focus down the spawning Profanes quickly as soon as the Wraith stops AOEing, and then continue killing the Wraith. Repeat during every Profane stage.
    
18. Make sure that your Ranged are not too close to the Wraith, as he will start to do other AOE attacks that damage nearby party members, such as rolling around. You will have to reposition your entire party every time the Wraith does this, to keep them out of its nearby range. Once again, make sure your melee attackers are spread out around the Wraith as well. It is also a good idea to pull the Wraith near a pillar or a wall, as you may cause him to Roll in one place if you position him properly, which means you don’t have to move around nearly as much to avoid his attacks.
    
19. When the Wraith starts to pull everything in, hide behind the pillars once again, until the spell is over. Repeat this anytime he casts the pulling-in spell.
    
20. Continue bringing down the Wraith avoiding his AOE.
    
21. Note: Make sure to also make heavy use of healing potions here on all of your characters, as the Healing from your Mage(s) will simply not be enough. Mana and stamina potions can also be useful.
    
22. Note: If the fight seems too difficult, put the difficulty down to Casual.
    
23. After you finish the fight, you once again have a choice of what you want to do; take the key, or fight the rock demon to get the treasures as well. It is suggested to refuse the demon and fight him for the treasure, as the fight is actually very easy.
    
24. Make sure to loot everything you can. If you find yourself with full bags, this is a good time to equip your other party members with some of the gear you collected on your journeys.
25. Head towards the door to the surface to finish the quest.