This quest can be obtained shortly before entering the city of Markarth. Tyranus, a Vigilant of Stendarr, will ask the Dragonborn to help him search an abandoned house for evidence of daedric activity. Upon entering the basement, Tyranus will proclaim that "This is no ordinary Daedra!" and run for the door, only to find it locked. Molag Bal will speak and command the Dragonborn to kill Tyranus. After he gives the command to kill Tyranus, the room starts to shake, the lights become dim, and objects move as if by themselves. If the player chooses not to kill Tyranus immediately, Molag Bal will convince him to attack. A Scroll of Calm will not prevent Tyranus from attacking, but casting Harmony will temporarily cease his attacks until it runs out, at which point he will resume his attack. Voice of the Emperor used by Imperials will calm Tyranus. Either way, Tyranus must be killed in order to progress any further. Afterward, journey down to the altar of Molag Bal in the basement.
Molag Bal entraps the Dragonborn in a spiked cage while activating the mace and says that he wants revenge on his rival Boethiah (another daedric prince) and her followers. He wants Logrolf the Willful, a priest of Boethiah who has been desecrating Molag Bal's altar in Boethiah's name, lured to him so he may break his spirit.
The location of Logrolf the Willful is randomized; any Forsworn camp may host him. Travel to his location and free him. If the quest No One Escapes Cidhna Mine has been completed, then the Forsworn holding him may not be hostile. If all enemies at his location are dealt prior to releasing him, he will immediately return to the abandoned house in Markarth.
Once back inside the abandoned house, follow Logrolf back to the altar. He will become trapped in the same cage that the Dragonborn stumbled upon earlier. Molag Bal will then grant the player his Rusted Mace and instruct them to break Logrolf's will. Attack Logrolf (any means of attacking can be used; the Mace doesn't have to be used) until he submits to Molag Bal. Once he submits, the Dragonborn is instructed to kill him. Do so to receive the Mace of Molag Bal and finish the quest.
This is a good opportunity to level up Restoration and attack skill(s) without fear of reprisal. Alternate between hitting Logrolf until his health is close to zero, and healing him back to full health. Keep doing this for as long as desired, but be sure not to kill him and that he does not submit too soon.
One can also level up the Sneak skill at the same time by sneaking at the same time.
The whole intro, with Molag Bal speaking, can be skipped if the Vigilant is killed immediately upon entering the house.
If Tyranus can't be found, he is known to spawn near the stables outside the city of Markarth and his dialogue remains as if he's near the abandoned house or ask a innkeeper if he has heard any rumors lately and this will automatically give the location of Tyranus when the rumor of the abandoned house is mentioned.
There is a Poltergeist reference when Tyranus decides to flee the house and get help. The table near the exit of the house has chairs stacked on it similar to a scene in the movie.
It is possible to obtain multiple Hooded Black Mage Robes from Logrolf during this quest, by quickly searching Logrolf after you kill him. When he is revived by Molag Bal, he will respawn wearing a new set of robes.
To fail this quest refuse Molag Bal and kill Logrolf in the pen.
If Dawnguard is installed,then two master vampires will spawn inside the house.
In the PC version of the game, when Molag Bal demands you kill Tyranus and the house begins to shake and hear loud noises. You can open the front door using the open command via the console. Tyranus won't leave, even though he knows his life is in grave danger. But if you go outside the shaking and sound effects will continue to happen regardless where you are and how long it has been. Nobody comments on it.
If the shrine holding the Mace is activated from the side or from behind, one will still be able to move around the room when talking to Molag Bal.
Activating the shrine from the side can sometimes get the player stuck inside the spikes with the character clipping into the spikes, but not letting them out. This can cause some problems with the dialogue, as Molag Bal sometimes won't enter into direct conversation, but instead just start talking, causing him to continuously start the conversation over and over. Remedied by waiting or loading the auto-save.
Not responding to the priest outside of the house the first time he is seen may make the quest unable to be started.
If encountering this common bug, leave Markarth and talk to a man named Banning about buying a war dog. Once purchased, the priest will be prompted outside of the house interrogating a local as he should. This process requires spending 500 gold and getting an unwanted dog.
Door of house does not lock automatically and may lock after talking to Molag Bal. This traps the Dragonborn inside of the house which requires a key to open the door. No fix known, revert to earlier save.
Upon striking Logrolf with the Mace, he may glitch out of the cage Molag Bal has erected for him. If this happens, it may become difficult to damage him enough to progress.
At random times, Tyranus will leave 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 ordering Tyranus be klilled. To get Tyranus to the basement hit him. Get him to attack, then run to the basement, once there kill him and the quest will progress.
An extension of the above bug, if Tyranus is killed while he stands in the center, and the Dragonborn leaves before going to the shrine in the basement, their 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 completing the Dragon Rising quest, and killing the dragon there. This seems to fix the coloration.
Also, if one goes to the basement without killing or hitting Tyranus, and wait for the shaking and discoloration to start, then leave, neither will go away.
The above glitch may be fixed by loading the auto-save.
Loading the autosave sometimes doesn't work.
Another way to fix this is to drink Sleeping Tree Sap. When the sap wears off one's vision should return to normal.
Like this bug, sometimes Molag Bal's narration won't go away. It might get stuck on the screen and pretend to continue talking if one draws a weapon as he starts to say it. Fix by killing Tyranus, even though the quest doesn't say to. No bounty added.
If Tyranus is pickpocketed and everything he has is taken he will not move deeper into the house. If the player goes into the basement and causes the house to start shaking and then gos outside the entire world will also be affected and will shake mercilessly. Upon returning to the house one can kill him and speak to Molag Bal, but the front door will now require a key and one will be permanently trapped inside.
After speaking to Molag Bal there may be some trouble exiting the house (you require a key). Load a saved game from before speaking to Molag Bal, kill Tyranus and exit the house.
If trapped in the house because of one of the various bugs, but have also killed Grelod the Kind for the quest Innocence Lostand haven't slept yet, sleep in one of the beds. The Dragonborn will be kidnapped by Astrid to the Abandoned Shack and thus, no longer trapped in the house in Markarth.
If one arrives in Markarth via the drinking contest from "A Night to Remember", the innkeeper at Silver Blood Inn might not have the appropriate rumor and will never have the appropriate rumor to start this quest and Tyranus will never be outside the house or outside the city. Even using console commands to force start the quest or spawn a Tyranus does not work in this case. The cause of this bug is that the Forsworn conspiracy quest does not start properly, as it is supposed to start with a murder in the market as one enters the town for the first time through the main gate *** It MAY fix this bug by going to the market, and killing Weylin while in sneaking. If done correctly the player will not get a bounty or be attacked and the other people will start yelling about the Forsworn attack, thus triggering the quest to proceed correctly. Afterwards the House of Horrors quest should start correctly as well.
There is also a bug that Molag Bal will not speak at all and will give no instructions to further the quest, kill Vigilant Tyranus as Molag Bal had spoken.
Stop the constant shaking by killing Tyranus and exiting the house without going to the altar, though there still may be problems with the visuals such as the gamma levels.
While beating Logrolf into submission he may pop out of the trap and stand outside of it. He is still unable to move and the quest is still completable.
While going back in the house it will say key required no fix known yet.
In some cases, when one enters Markarth, Tyranus will be hostile and the quest "The House of Horrors" cannot be started. To fix this, lead Tyranus out of Markarth, away from the city gate, next beat and/or slash at him until he gets down on one knee (at this point he is unkillable). While he's on one knee, quickly run back into Markarth (the Whirlwind Sprint shout could be helpful). Then when one comes back out of Markarth, Tyranus should be where he was left, and no longer be hostile. At this point speak to him and begin "The House of Horrors" as one normally would. Another way to fix this bug is to use a spell of Calm or Voice of the Emperor, after which Tyranus should be non-hostile and allow the quest to begin.
360 PS3 Sometimes the trap is not triggered when the mace is first taken and the quest does not continue. This is solved by using Telekinesis on the mace.
This can also be solved by using the disarm shout on the mace and then grabbing it.
It is possible to get stuck at the beginning of the quest. When Tyranus enters the house, if a guard sends the Dragonborn to jail, the door will be locked again when they come back.
If the quest marker to 'Find the priest ofBoethiah' appears west of Sundered Towers then the quest marker may not show up on the compass and he will not be there. If this happens just wait till the next day after killing all the forsworn and he should appear in a tent near the anvil.