Rumour spreads that an unknown adventurer brought a mutilated and disfigured corpse into town, the corpse had the symbol of Lolth carved into it and was found in the firelizard caves behind the door leading down into the underdark. Clearly this was a warning meant to keep any trepassers out.
The somewhat devilish looking corpse was raised and the tiefling now walks the surface realm once again with no recollection of how he got that scar.