Mist and Shadow [Quest]

Text of the Quest:

Something strange is happening in Shademist Moors. The village of Longhaven needs someone who can uncover what might be behind it. The residents of Longhaven report that people have been disappearing into the fog over the moors. I've been told to talk to Breduin for more information.

Heluin: Turn back. That way's bad omens. Even the air's turned against them in Longhaven.
Hero: What do you mean by that?
Heluin: The moors have always been a wild place, covered in thick fog. But for us who've known them our whole lives, it's home. Now, though, people've been disappearing into the mist. We find their bodies later, torn up and drained of blood.
Hero: What do you think is the cause?
Heluin: It's a reckless curiosity drives a person to look for cause in such things. Me, I'll take ignorance and a long, happy life in Marbruk or Woodhearth. But if you got to know, you might talk to Breduin in his hut in town. He's staying, poor fool.
Hero: I'll speak to Breduin.

Breduin: Welcome to Longhaven. Used to be a busier place, before all this trouble with the mist. But we won't let that be an excuse for poor hospitality.
Hero: Trouble with the mist?
Breduin: Started a few weeks ago now, when the mist... changed. Turned a sickly color.
Hero: What happened?
Breduin: All I know is what I saw with my own eyes. Hunters simply dropping their bows and wandering unarmed into the moors as if bewitched. Then their bodies turn up later, or what's left of them. Can't explain it. Except....
Hero: Except what?
Breduin: A wanderer much like yourself—a dour Dunmer fellow—passed through here. Bought supplies and headed straight into the moors, my warnings be damned. Seemed like he knew something. You want to figure this out, I'd start by finding that Dunmer.
Hero: Have you been out there yourself?
Breduin: No, only the hunters. I manage clan affairs and the upkeep of the village. This was simpler before the forming of the Aldmeri Dominion. Valenwood is changing, and its people with it. I find my time occupied in dealing with the necessary adjustments.
Hero: Can you tell me more about this Dunmer visitor?
Breduin: He was gone as quickly as he came. He was outfitted for battle, though that isn't strange for adventurers. But he walked as one who knows his goal, and will not be deterred.
Hero: Has anyone that ventured into the mist returned?
Breduin: Strangely enough, several. They all reported an odd sensation that wasn't present before, as well as an apparent rise in hostile beasts in the area, but otherwise returned unscathed. If this is some spell, maybe some are more resistant than others.

Mel Adrys: Begone. I must finish my prayers and purify my spirit before I meet my foes in battle.
Hero: Why are you out here?
Mel Adrys: I have been tracking my prey for many nights. A heathen vampire who shall soon be cleansed from this world. I thought him alone, but now that I see this place I suspect a lair is hidden nearby. He shall regret leading me to his vile nest.
Hero: Could that explain this strange mist?
Mel Adrys: I have hunted them all my life, and yet I have never seen magic such as this. I do feel their touch upon it. I feel it testing my will with every step I take. But I shall not falter. I shall face these creatures and leave nothing but ash behind.
Hero: Let me accompany you.
Mel Adrys: No fear. Bravery, or foolish inexperience? I cannot trust one who could become enthralled at any moment. Prove to me you have the will to resist this foul magic. Find me at the lair up the hill east of here. Then I shall consider it.

Mel Adrys: So you made it through the mist. Your will is stronger than I expected.
Hero: Who is this?
Mel Adrys: Vampire scum. He barely put up a struggle before he fell to his knees, begging for what he calls a life. I did not expect such weakness. I will finish him now, if you'd be so kind as to step aside.
Hero: This is the one you were hunting?
Mel Adrys: No. This pathetic being is hardly even worthy of my blade. The one I followed here is called Faenir; a much more formidable foe than this maggot, I assure you. We shall meet him soon enough. He and all of his coven shall die.
Hero: He could have information we need. Let me speak with him first.
Mel Adrys: As you wish. In this moment or the next, his existence shall end either way. But be wary. A vampire attempts to sway and beguile with its words. Do not listen, no matter what he says.

Gadinas: You must have mercy! The Dark Elf won't listen, but you will, won't you? We were different! I didn't want this!
Hero: What do you mean?
Gadinas: Kept to ourselves. Didn't prey on the living! The beasts, the hoarvor glutted themselves on the blood of hunters. We fed on them. We didn't kill anyone. It was a natural way. Until he came.
Hero: He?
Gadinas: The veiled one. Altmer, I think. Sought an alliance. Promised power. Told us we didn't need to hide anymore. Others in my clan agreed. He taught them a ritual using an ancient vampire's skull. Said it would allow them to make countless thralls.
Hero: Tell me how to put a stop to this magic.
Gadinas: The skull rests in the back of this cavern. Its curse seeps into the mists all around us. Destroy the skull and the magic goes with it. I never wanted this. Spare me and I can bring others to my side. We can be of use to you!
Hero: Was Faenir among those that accepted the veiled one's offer?
Gadinas: Yes, he was the loudest of the supporters along with Athraedal and Lathriel. I saw them speaking with the veiled one often. They'd never listen to me. You'll have to go through them if you want to reach the skull. Now please, just let me go.

Mel Adrys: Finished with your little chat? I shall relieve him of his head now and rid us of his insufferable mewling.
Hero: He was forthcoming with information. We might benefit from having him alive.
Mel Adrys: Did I not warn you of this? That his vile tongue would worm its way into your thoughts? There's no such thing as a good vampire, just a vampire that has not yet been tempted. Our goals here are the same. Will you forget them for this scum?
Hero: We gain nothing from his death right now. Leave him or go through me to get to him.

Breduin: It's you again! The hunters say the mist has lost its sickly tint. Did you find the source?
Hero: Vampires were using the mist to create thralls of your hunters.
Breduin: Vampires, here? Sickening. Hunted in our own hunting grounds. We'll be more vigilant of their kind now. I'll see to it personally that every last one of them is destroyed. Thank you for helping us.
Hero: Complete Quest.