Skyrim:The House of Horrors

Quick Walkthrough
#Enter the Abandoned House.
#Kill Vigilant Tyranus.
#Speak with the Daedric Prince Molag Bal.
#Release Logrolf the Willful.
#Make Logrolf bow to Molag Bal, then kill him.
#Receive the Mace of Molag Bal.

Detailed Walkthrough
The Witchhunter
thumb|right|Tyranus interrogates...
In Markarth, the innkeeper at the Silver-Blood Inn may tell you that a witchhunter from the Priesthood of Stendarr recently showed up in town, asking all sorts of questions about the old abandoned house up the street from the main gate. Whether or not you've heard this rumor, you will find Vigilant Tyranus wandering around outside the house, at times bothering the townsfolk with his questions. When he sees you he will actively seek you out and ask if you know anything about the house. Unless you totally reject his questions, he will introduce himself, obviously hoping for a helping hand, and proceed to explain that he believes the house is home to Daedric activities. Agree to help him and he will invite you to come along for the investigation and unlock the door.

The Abandoned House
Upon entering the house, everything appears normal, and a puzzled Tyranus comments that it shows no sign of old age as there is fresh food on the table and no wood-rot on the furniture. Immediately after he stops talking, a loud noise comes from downstairs. Tyranus then takes off running towards the noise, only to be stopped by a locked door. He then asks you to open it. The door is locked, and triggers a voice inside your head:
:'''''"Weak. He's weak. You're strong. Crush him."''

At the same time, the furniture and items in the house will start floating in mid-air, causing Tyranus to panic and run upstairs, yelling, "Stendarr's Mercy! This isn't an ordinary Daedra. We have to get help." He will then run all the way upstairs, only to be impeded by the front door, which is now locked tight. He asks you to leave first and when you touch the door, the malevolent voice will once again resonate, not only in your head, but in that of Tyranus as well:
:"No. Kill him. Crush his bones. Tear at his flesh. You will kill. You will kill, or you will die!"
thumb|right|"Stendarr's Mercy! This isn't an ordinary Daedra."
Tyranus will slowly start to panic and forget his righteousness, shouting to the unknown entity inside his mind. When he eventually realizes that there is only one way out, he will draw his mace and proceed to attack you, succumbing to the orders of the mysterious Daedra in the hopes of preserving his own life. He will use several spells, including sparks, lesser ward, healing and oakflesh, determined not to die in the haunted house. Unfortunately, you are in the same situation and will have no choice but to defend yourself, with an inevitable outcome. This seems to amuse the voice:
:"Yes. Your reward is waiting for you, mortal. Further down."

The previously locked door is now open, and leads further into the house. Past this door, the voice leads you through a food storage larder, where a hole in the wall reveals a subterranean tunnel, which leads to an altar where your reward, a rusty mace, awaits.

Molag Bal, Lord of Domination
When you try to grab your reward, a set of spikes will immediately shoot up from the floor and trap you in place. You can do nothing but face the altar as it now speaks directly to you: 

: "Fool! Did you think Molag Bal, the Lord of Domination, would so easily reward you? What do you see from that little cage? Speak."

The voice belongs to the Daedric Prince Molag Bal, whose main ambition and desire is to harvest the souls of mortals and bring them to his own Plane of Oblivion. You now have three dialogue options. You can tell him you see a rusted mace, and he will say: "Rusted. Dry. There was a time when this mace dripped with the blood of the feeble and the worthless. But a Daedric Lord has his enemies, and my rival Boethiah had her priest desecrate it. Left it here to decay. Until you came."'' If you instead tell him it's an altar, he will reply: ''"Yes. It's an altar. Men would come and sacrifice the wretched in my name. The weak would be punished by the strong. But a Daedric Lord has his enemies, and my rival Boethiah had her priest desecrate the altar. Until you came." You can also tell him you only see the spikes of his trap, to which he will respond: "Sharp, aren't they? This was the last thing many saw before they were sacrificed in my name. But a Daedric Lord has his enemies, and my rival Boethiah had her priest desecrate it. So long since it's tasted blood. Until you came."

Depending on your response, he will then say either:
: ''"Revenge? No. I want submission. I want the priest who did this to bend his knee and give me his soul. He comes by to perform Boethiah's insulting rites at my altar, but he's been missing. Captured and bound. Left to rot. Save him. Let him perform his rite one more time. And when he does, we will be waiting for him."''
or
: ''"Fine. I offered you a reward. You'll get the freedom your kind enjoys so much. But Boethiah's priest is imprisoned as well. But not by me. He is hurt. Suffering. Save him. Let him perform his rites one more time. And when he does, I will be waiting for him."'''''

The altar will then be quiet and inactive, patiently waiting for you to "rescue" the unfortunate priest and bring him back to the altar, so that Molag Bal can bring yet another soul to his realm. Your quest journal will update and point you towards one out of six possible locations, all located in the Reach and inhabited by Forsworn, who are the ones responsible for imprisoning the priest of Boethiah. Leave the house and altar behind and travel to the specified location.

Possible locations:   thumb|right|Logrolf the Willful

The Pious Priest of Boethiah
When you find the dungeon, make sure to clear the place entirely of Forsworn, as the captive priest will attempt to make his own way out of his prison. When you finally locate the captured worshipper of Boethiah, he turns out to be an elderly, grumpy priest named Logrolf the Willful. He will be tied and kneeling and will, despite his precarious situation, have quite a bit of a high and mighty attitude, referring to himself as 'the mighty Logrolf'. When you tell him you are there to rescue him he will immediately become suspicious: "Rescue? No one knew where I was, when I was taken. Who sent you?" 

You can now choose to persuade, bribe or intimidate him. Note that you need a Speech skill of 50 to successfully persuade Logrolf:
 


After you have untied his binds, he will take off running towards Markarth, determined to single-handedly save humanity once again in the name of his beloved Boethiah. Make sure he gets out safely, then travel to Markarth and re-enter the abandoned house.

You can also choose to kill him at this point. Doing so will fail this quest.

Make Him Bend to Me
Inside the house, the oh-so righteous priest will head right into the basement, without thinking twice. When he reaches the foot of the altar, Molag Bal will trap him right away and a conversation will take place:

: 
:Molag Bal: "Ah. But I have my own champion this time, Logrolf." 
:   Logrolf: "What? You!" 
:Molag Bal: "Mortal. I give you my mace, in all its rusted spitefulness. Crush the spirit from Logrolf's bones. Make him bend to me."''

The rusty mace will then be equipped and you will have no other choice than to help Molag Bal humiliate the elderly man. You will have to repeatedly beat the defenseless priest as he quivers, and ultimately kill him. Once he is dead, Molag Bal will revive him, ready for yet another beating. When Logrolf's spirit is finally broken, he will bend before Molag Bal as requested: 
thumb|right|''"You're mine now, Logrolf."
:Molag Bal: "You bend to me?" 
:  
: Molag Bal: "You pledge your soul to me?" 
:  
:Molag Bal: "You forsake the weak and pitiful Boethiah?" 
:  
:Molag Bal: "You're mine now, Logrolf."

With the victory, Molag Bal will lose interest in the torture session and will, mercifully, ask you to put Logrolf out of his misery. The frail old man is already weakened considerably and will not be able to defend himself, so kill him right there in the cage. Lastly, a triumphant Molag Bal will turn the rusty mace into the Mace of Molag Bal, finishing the quest with the words:

:''"The Mace of Molag Bal! I give you its true power, mortal. When your enemies lie broken and bloody before you, know that I will be watching. Now, I have a soul in Oblivion that needs claiming. Take care of the house while I'm gone. Ha ha ha!"'''''

Notes
If you don't enjoy being pushed around by Molag Bal, or find the prospect of sadistically beating a caged man to death distasteful, there is a way to defy him and still gain from the quest, while simultaneously denying him the soul he desires. See Enthir at the College of Winterhold in his quarters, or the wizard Falion in Morthal and purchase a black soul gem. Go then to Markarth and break into the Inner Sanctum of the Temple of Dibella and interrupt their ritual, initiating the quest The Heart of Dibella. It is highly likely that the priest of Boethiah which Molag Bal covets will be in the same holding cell where you must rescue the young prospective Sybil. When you find them, cast a soul trap on Logrolf the Willful and slay him on the spot. You then walk away with a black soul, deny Molag Bal what he wants, and save the Sybil for the priestesses of Dibella all in one fell swoop.
When first entering Markarth, Vigilant Tyranus will not be present due to the Forsworn-related scene in the market. After the scene, exit and enter Markarth (or any other zone, including shops), and he will spawn. If your first entry to the city is via A Night to Remember and it is nighttime when you exit the temple, the market scene will not play. In this case you need to first wait until daytime and then enter the Markarth zone to activate the market scene, then leave and re-enter to make Tyranus spawn.
If you wish to loot Vigilant Tyranus's body, do it right after killing him. His body will disappear when you return with Logrolf.
If Logrolf's location is Druadach Redoubt and you've already helped Madanach escape from Cidhna Mine, it is not necessary to clear the area of Forsworn.
If you kill Logrolf while he is being held captive, the quest immediately fails and you will miss out on the Oblivion Walker achievement. The shrine in the Abandoned House becomes inactive and you receive no rewards.
You can use the abandoned house as a home as the containers do not respawn and the bed is free to sleep in.
If you like, you can keep the Rusty Mace by storing it on a weapons rack. You are not forced to use it to kill Logrolf, and you will automatically gain Molag Bal's Mace once the deed is done.
The entire killing of Logrolf sequence is a scripted event and doesn't count as a murder.
If you also have the Heart of Dibella quest active, and the location of Logrolf is Broken Tower Redoubt, he will be in the same prison cell as Fjotra.
Logrolf can be the target of soul trapping effects. Killing him when ordered to break his spirit will result in the gain of a black soul, before Molag Bal resurrects him. This can be used an indefinite number of times, providing a handy risk-free method of obtaining black souls, with no associated bounty. You can soul-trap him one last time when ordered to kill him. 
If, at stage 100, after you beat Logrolf to death and Molag Bal revives him, you then use the console command setstage DA10 140, skipping stage 130, you effectively thwart Molag Bal by allowing Logrolf to live and depriving Molag Bal of the soul he thinks he will be enjoying as a snack. Logrolf remains immobile with no dialog options while you remain. As you leave the Abandoned House, however, you will observe Logrolf also leaving, and if you follow him he marches straight to The Warrens and tries to enter Degaine's now-empty room. He may get stuck at the door, and if you open it for him he may get trapped behind it, unable to pathfind his way around the now-open door. If you can force him from behind the door, he will enter Degaine's room halfway and then just stop and stand there.

Bugs
 
 
 
Open the console and type   and   to get the Mace. You can then enter the Abandoned House using the console command   after clicking on the closed doors, and you can even speak to and eventually kill Logrolf with the commands  , then  , and finally  .
 
 
Open the console and type   with a location such as  . You will be transported to that location and the dialog will begin again.
 
 If you cannot find him, use   to go to him, then follow him back to Markarth and proceed as normal; using   is not recommended as it will cause the script to malfunction.
 If the solution above does not work and you're more inclined to go through with the quest than simply acquiring the mace, you can alternatively use the command  , get in the house, sparing you of the conversation, and once inside you can kill him and go on with the quest.
 
 
 
 This can be bypassed by opening the console and typing  , granting you the normally unobtainable key to the bugged door.
 
 

Quest Stages