Tyranus, the Vigilant of Stendar in Markarth who starts the quest for Molag Bal, has disappeared.

I have back out of the conversation a few times, and I am playing as a Vampire. Now he is gone. I have searched every nook and cranny of the City of Markarth and he is nowehere to be found. Tried some of the wiki suggestions and they did not work, so now I am here asking for help.

Is he gone for good or do is ther a chance I can bring him back by getting rid of the Vampirism?

EDIT: Xbox 360 Player. Console Commands Not applicable.

was he killed during a vampire attack?

have you changed Markarths allegiance through either the CW or Season Unending?

I was a vampire and I still did the quest.

Did you try and reload a past save?

Nope. haven't even touched the Civil war or the main quest

I would, but the last time I saw him is too far back.

It should be impossible for him to be killed by a vampire attack or any other means, since he is marked as essential until the first stage of The House of Horrors has been completed. I have heard about other people having him disappear too; there is apparently only one solution and that is reloading a previous save before he disappeared.

Here is one possible reason why this bug may occur (according to the http://www.uesp.net/wiki/Skyrim:The_House_of_Horrors#Bugs):

If you enter Markarth for the first time while completing the A Night to Remember quest and it is nighttime, the incident in the marketplace which initiates The Forsworn Conspiracy will not have happened. This prevents Vigilant Tyranus from spawning, thus preventing you from starting this quest.

Have you tried entering the Abandoned House?

Also, I believe I have encountered him OUTSIDE Markarth between the gate and the river.