The House of Horrors

Overview

 * Prerequisite: Kill Vigilant Tyranus 
 * City: Markarth
 * Quest Giver: Molag Bal 
 * Reward: Mace of Molag Bal
 * Reputation Gain: N/A

Background
"I have met Molag Bal, the Lord of Domination, He has asked me to cleanse his altar in the abandoned house in Markarth by luring a priest of Boethiah to him."

Walkthrough
This quest is given when you visit the Hold of Markarth. You will search an abandoned house with Vigilant Tyranus. (if he is not there, refer to this video: Skyrim - House of Horrors (Trouble starting the quest?)) Once you get down into the basement Malog Bal will speak and command you to kill Vigilant Tyranus or if you choose not to, Vigilant Tyranus will try to escape but the front door will be locked and Malog Bal will convince him to attack you. Either way you must kill him, do so and journey down to the altar of Molag Bal in the basement.

Molag Bal entraps you while activating the mace and tells you that he wants revenge on his rival Boethiah and his followers. He wants you to lure Logrolf the Willful, priest of Boethiah to him so he can take their soul.

The location of Logrolf the Willful is random, any forsworn camp can host him. Travel to his location and free him, be sure all enemies at his location are dealt with as he will immediately run to Markarth.

Once inside the abandoned house follow Logrolf back to the altar. He will become trapped and Molag Bal will tell you to take up his mace and bash Logrolf to death. Attack Logrolf (you do not need to use the Mace) until he submits his soul to Molag Bal. Once he submits you are then told to kill him. Do so to receive the Mace of Molag Bal.



Trivia: the dining table having stacked chairs and the fact the house is haunted is a reference to the movie "Poltergeist".
 * Detailed video walkthough available here

Bugs
At random times, Tyranus will enter the house and then enter again. The problem with this is now he will continue to stand in the center of the first room instead of going deeper into the house. This will make the quest impossible to complete due to the basement needing a key to open and this effect can only removed by the Daedric Prince telling you to kill Tyranus. A way to force Tyranus to the basement is to hit him. Getting him to attack you then run to the basement, once there kill him and the quest will progress.

An extension of the above bug, if you kill Tyranus while he stands in the center, but leave before going to the shrine in the basement, then your vision may be permanently red and hard to see with, and seemingly as impossible to fix as the above bug. This can be fixed by going to Shearpoint, after you've done the Dragon Rising quest, and killing the dragon there. This seems to fix the coloration. I have not tested it yet, but it may also fix the rest of the bug [i.e. not being able to leave after talking to Molag Bal.]

It's not really a bug, but when you return to the abandoned house to hit Logrof with the mace to death, you can easily keep leveling up by healing him and beating him with the mace. This will make you go higher with restoration and one-handed skills. Keep doing it until you're bored.

If you pickpocket Tyranus and take everything he has he will not move deeper into the house. If you go into the basement and cause the house to start shaking and then go outside the entire world will also be affected and will shake mercilessly. Upon returning to the house you can kill him and speak to Molag Bal, but the front door will now require a key and you will be permanently trapped inside.

After you speak to Molag Bal you may have some trouble exiting the house [you require a key]. If you have a saved game before you spoke to Molag Bal load it up, kill Tyranus and exit the house. My vision hasn't changed at all.