Quest: Dagon Shrine

After entering the shrine, you'll be presumed to be an initiate of the Mythic Dawn - after all, who else would be likely to wander into this remote cave?

The doorkeeper will let you in to speak to Harrow, one of the mucky-mucks in the cult. Now, at this point, you have a couple of options: you can hand over all of your possessions to Harrow, who'll give you back a Mythic Dawn Robe to wear, or you can start chopping heads and work your way into the cave to retrieve the Amulet of Kings the old-fashioned way.

Violent Way

Get everyone's attention from here, then drop down and grab the book before making a break for it.

So you want to kill a whole mess of cultists? Well, have we got an opportunity for you. The goal at this point is to just start chopping: kill the doorkeeper, Harrow, then walk into the caves behind them and start dealing with all of the cultists in the small chambers beyond. Note that the Acolytes don't change into full armor when you attack them, but also that they'll run away when they're near death. Annoying, that. Feel free to loot the Mythic Dawn's storehouse if you can pick the Hard lock; there isn't anything tremendously exciting.

When you exit into the Dagon Shrine, no one will initially be on your case, so feel free to sneak around a bit. Your goal is to disrupt the sacrifice meeting here, steal the Mysterium Xarxes (since Mankar disappears into Oblivion when he spots you), and make it out alive. Then you must defeat the dread Xenium Kinneget and replace the Scepter Rune of Obnoxium! Well, no, we're kidding about that last part.

If you sneak around to the southern overhang that looks over the cultists spread out below, you can get their attention with a Flare spell or something similar, wait for the bulk of them to run up the stairs to the north and circle around to get you, then drop down to the floor, free the prisoner on the altar (optional, but the Right Thing to do), grab the book off the podium, and head out the north exit to the Shrine Living Quarters. Obviously, things are going to start moving pretty fast, so now would be a good time to take off all your heavy armor and take any potions or cast any spells that add to your speed or fortify your health.

When you grab the Xarxes, all of the cultists that you distracted earlier on will be back on your case, and probably coming down the steps. If you don't want to run directly past them, try hiding behind the shrine here and waiting for the bulk of them to approach. They'll zap you with lightning, obviously, but if you wait for them to get close you'll have an easier time getting up the stairs and heading to the Living Quarters exit, which was locked before, but will be open to you now. When you pass through to the Living Quarters, re-equip all of your armor and weapons and turn around, facing the door. Usually, no more than two of your pursuers will follow you through the door; if they're Acolytes, you stand a good chance of killing them or forcing them to run, which might give you a breather you can exploit and let you take your time when traversing the Living Quarters and making your way to the exit.

Undercover Option

If you decide to go undercover, there's something you can do to prevent Harrow from taking all your loot: drop it. In the exterior area before the doorkeeper, just drop everything you own on the ground, including your armor, weapons, potions, etc. Most of the stuff should be easily pick-up-able later on, but especially small items, like rings, should be dropped somewhere separate from the rest of your loot, preferably in a well-lit area of the room, since they'll be tough to find later on. With all of your stuff on the ground, you can talk to Harrow, give him a whole bunch of nothing, then walk back to your loot and pick it all up.

The only thing that Harrow will keep in this instance is...drumroll...all of your gold. You'll be able to kill him later to get it back, but this can be difficult, especially if you're a stealth character, so if you're worried about your roll getting taken permanently, invest it beforehand in something, like expensive equipment or training.