Leave through the door behind the Chantry. When you get outside, talk to Alyn Shir. Be sure to loot the chests on the way down the path to Camp Moondown. Stock up at the shop, smith anything you need to and then head down from the camp. Make your way E along the main road and take out the small camp of Tuatha. Follow it S and then to a small pass which leads to Shadow Pass. You'll come across a group of 5-6 Sprites but they are a little tougher this time. The real thing to watch for is the Ice Sprites because they have a projectile Ice attack that they can control to follow you. In some cases, it might be more worthwhile to let it hit you if you can't get it to hit a rock or something. Kill them and continue S.
NOTE: From here, it's actually possible to just run straight through the end of the pass. You will want to do that until you get to a point where there is a Quest Marker for Cydan. After that, you have to fight.
After you pass by Ariad Camp, you'll come to a Tuatha encampment. Just to the W will be a small path that leads up to the W. Take it and kill the Tuatha at the top. It's probably best to draw their attention and then pull them back a little so you only fight a couple of them. Check the chest and then jump down from here. The next group of Tuatha nearby is actually all melee and should be quite easy. Kill them and continue along Shadow Pass.
The next group of Tuatha is similarly all melee but there's more variety to them and there are far more of them. Use your AoE attacks to make easy work of them. As you go up the slope behind them, you'll be attacked by a Tuatha Soldier! What they don't tell you is that there is a Prismere troll just behind her and two Tuatha Priests on the sides that you can't see. This might be a good time to use Fate Shift. I would recommend just trying to take down the Tuatha. Fighting a troll is nothing new to you but trying to balance the magic, fast and slow melee attacks of the group can be quite tedious.
Not long after that is another group of Tuatha. Mostly melee but they may have an archer amongst them. Kill them and then in the next pass you'll come to another Tuatha/Troll combo. It's easy enough to lure the Tuatha away from the troll so do that and then let loose on him too. The Tuatha should all be melee, making this an easy fight.
After this, you're going to start encountering very large groups of Sprites similar to the ones you faced before. If you are feeling brave or comfortable in dealing with them, go for it but between the Fire, Lightning and the homing Ice attacks, they can be quite difficult unless you are well leveled. You'll also face some Murghaen and Murghaen Priestesses. You'll finally return to Tuatha camps but there are a lot of them and you either want to run through quickly or fight through very slowly. Either way, work your way through the big camps and you'll come to another Tuatha/Troll fight.
Make your way past them and as the road turns N; you'll come to another small camp with Cydan in it. Help him with the enemies he's fighting and then talk to him to find out that Agarth is on his way. When Agarth arrives, you can push through to the final fight. Before you go, though, there is a dungeon to the E that you can run over to so that you get a quick travel marker (but watch out for the Troll). Then feel free to stock up on supplies. When you are ready, return to Cydan.
From this point, you'll actually have to fight, no running through because Cydan has the key to the House of Vengeance up ahead and he's going to stop and fight everything. Make your way through the groups of Tuatha in the camps and into the castle. Inside, the first room will be quiet but the second room will have an overwhelming number of Tuatha. Just start spamming some kind of AoE attack. Cydan and Agarth will keep them busy while you kill them. After the fight, follow after Agarth and Cydan. There will actually be some Tuatha up ahead on the left side of this room but if you play your cards right, you should be able to stay out of the way of them. You'll climb some stairs and come to a square room with a raised circle platform in the middle. Then you will be attacked by half a dozen Tuatha Priests. I HIGHLY recommend using a Fate Shift here. Clear them out.
You'll go down a curved hall to a rectangular room but all of the Tuatha in here will be melee or marksmen types. This should be far easier than the room you were just in. The next room will be a mixed room of close range and Tuatha Overlords. I recommend that you get up close to the Overlords and try to kill them first. It requires a little luck but sometimes if you keep moving and Agarth and Cydan try a little, you shouldn't have too many soldiers to worry about while you're doing this. Once they are dead, cleaning up shouldn't be a problem. If you continue down the hall behind them, you'll come to a small fight with a small group of soldiers and a single priest. Again, just rush for the Priest and take him out, then clean up.
The Cur of Vengeance
The Cur can be quite a tough fight. On hard, some of his hits can kill instantly. When you start the fight, try and keep your distance from him. If he chases you, run and let Agarth and Cydan soak up the damage from him. Focus on killing the little enemies. Kill the Tuatha and then start hitting the Cur from a distance. If he turns to you, run away and let him cool off first. After a little bit of a beating, he'll teleport away and summon three Niskaru. Spam a lightning AoE attack if you have it. Once they are dead, you can go after him again. After a little while he will resummons Niskaru. And this is how the fight should go. Keep running from him, killing the Niskaru and then turning on him until he summons more Niskaru. Every summon after the first will only bring two Niskaru instead of three. Once you get the hang of his pattern and can manage to get him to lay off, this fight can be quite easy.
If he comes after you and hits you, don't be shy about healing though because even if he doesn't kill you with one big hit, usually that means he's going to go into a combo that will kill you if you don't heal.
Once he's dead, make sure to grab all the loot, there should quite a bit of good stuff in here. Head out the back of the House of Vengeance and you'll be greeted by a familiar face to fill in the last pieces of the puzzle for you. This will be a rather long winding road. It will be filled with Tuatha, Trolls and occasionally Niskaru but this shouldn't be anything new for you. As you cut through each group, Alyn Shir will fill in more and more about your last moments before you died. When you start getting close to your destination, save because you will have a persuasion attempt coming up and even with Persuasion maxed out, I still only had a 75% chance to pass it. Make your way through the big doors to find Gadflow.
Gadflow
Gadflow seems hard at first but once you get his pattern, he's a cake walk. He will start the fight by splitting himself into three. The "real" Gadflow is the one that doesn't glow. However, that doesn't mean you want to focus just on him. In fact, you want to split your attention between Gadflow and his two copies. Each Gadflow will use a different spell but the real Gadflow's attacks are the most damaging. You need to kill the two copies as quickly as possible but you always want to keep an eye on the real Gadflow. If he starts to get ready for his whirlwind attack, hit him to cancel it.
The reason you play this balancing game is because allowing the real Gadflow to hit you can kill you in one hit, maybe two (and sometimes those two will hit you almost simultaneously) but if you focus just on him, the copies will keep hitting you with spells that cancel your own attacks, meaning you do minimal amount of damage while using a large number of potions. The difference for me was between using about 20 potions and using 3. However, you must be quick because it's time, not an amount of damage that starts his next attack phase.
After a certain period of time, the copies and Alyn Shir will disappear. Gadflow will teleport to a side of the room and then lay a bunch of red circles on the floor. Don't step on the circles because they explode. You want to get to the far side of the room from him as quickly as possible because it will have a rather large area without any of the traps. At the far end, he'll charge up a fire spell that moves across the floor. When it gets close to you, dodge out of the way. Be careful though because you don't want to move too far forward while you're focusing on your dodging lest you land on a trap and you don’t want to dodge too early or the fire will correct for it and still hit you. After dodging several shots, he will get rid of the traps and move forward. He will then summon his two copies again and then teleport so all three of them are spread out.
If you are a Sorcerer or just happen to have the Healing spell, you can use it after you kill the copies and in between volleys on Gadflow and after he finishes his trap routine. This will help keep potion usage down.
Pattern: Attack copies and occasionally Gadflow, Attack Gadflow, Run away from Gadflow when he lays traps, dodge fire attacks, healing spell (if applicable). Rinse, Repeat.
