Guild Wars 2 – Hidden in Darkness

Head over to Hemlock Coil. It is time to start the next part of the story mission for those who chose disguise.
Caithe: “You've arrived just in time Valiant. I scouted the Nightmare Court Camp, and fortune favors us. The white stag is not yet corrupted. However, that is where our luck ends. I saw a patrol guarding the outskirts of the camp, and several more courtiers within. Freeing the stag will be difficult.”
Hero: “My plan is to disguise ourselves and sneak into the main camp. Once there, we can free the stag and use stealth to escape. We'll need to steal some of their clothing so that we look like the other courtiers. Then we can move about freely.”
Caithe: “A good plan, but we must be cautious. The camp's leader is Sariel, a cruel and prideful sylvari. She may notice that we are not what we seem.”
Hero: “Then we'll just have to make sure she's not around while we search. Maybe we can play to her flaws. After we find the cage where they're holding the white stag, we'll set it free and fight to cover its escape.”
Caithe: “Deception, mayhem … I'm going to enjoy this plan. Very well. Let us go and find that patrol.”

next is a simple matter of waiting for about a minute. There is a patrol fast approaching your position. Wait for them to get close then tear into them. They are all lvl. 8 and a fairly missed group. Just fight them quickly and brutally. There is no a lot to worry about here.

Once the whole group is done for you can head over to the Northwest, toward the marker. Most other routes will lead you into areas you need to fight a few creatures and some Nightmare Courtiers.

When you make it to the edge of the court's camp you will be admitted without question. Just head straight in and you will find Sariel. She immediately threatens you and tells you to listen to her. Now you need to convince her to leave the camp. One way is to talk with her and tell her that the camp in Dorous Vale is under attack. She will respond very well to someone commending her combat prowess.

With all of them gone it is time to head back to the North. From there turn to the West as soon as you can. Explore though the roots and vines here to find the prison. Here you will find 3 cages. Each one has a prisoner. The first has Sylvari while the second has the White Stag you are after. The third one has a second Sylvari that is being help captive. Free them all then it is time for a much bigger fight to happen.

While you do not need to revive the prisoners, it helps a lot. They are additional aid in the fights. For the mage/scholar classes, this can make the difference of having to restart from a check point.

It starts simply enough with 5 lvl. 8 Courtiers of differing skills. Beat them then head to the Southeast down the slope. Another 4 Courtiers will appear and attack you. At the first landing you will encounter a pair of Nightmare Thorn Hounds. They will be backed up with at least 5 Courtiers (among them a Knight and Minstrel as well). This is a bigger fight so keep on your toes and think about how you can best get through it.

Head down the next slope and another set of 5 Courtiers will attack your small group. Just keep at it. There are only a few more groups to get through before the instance is through.

At the end there is another conversation with Caithe:
Hero: “That was tremendous! The disguises worked perfected. How did you know we could cinvince their leader to leave the camp?”
Caithe: “I know her. Her name is Sariel, and before she fell to the Nightmare, she was the student of someone I loved very dearly ... but that is a story for another day. The White Stag seems uninjured, though understandably frightened. I'll take him back to the Grove. Be warned, Valiant. Sariel is prideful, above all else. She will not forget this insult.”
Hero: “Yes, but you're taking the stag back to the Grove. Sariel wouldn't actually attack the Pale Tree's city just out of wounded pride … would she?”
Caithe: “You underestimate the Nightmare Court. They will do whatever they must, to get their way.”
Hero: “At least Gavin still had a sense of honor. How can he and Sariel both be in the Nightmare Court?”
Caithe: “Evil has many forms. Some desire tyranny. Others, chaos. Regardless, they will come for the white stag, and they do, we must be ready. I will meet you at the Grove.”