Erthor is a Bosmer sorcerer found in Bleak Flats Cave. While he is a member of the Mages Guild, he is not allowed to do his research in Skingrad Mages Guild due to a "Scamp incident" the previous year.
In order to get a recommendation from Adrienne Berene, she will ask for help in locating Erthor. She and the rest of the guild members will note how he has not been in contact recently and they are starting to worry.
After talking to several members of the Guild hall, it will be discovered he works out of Bleak Flats cave and that it we normally comes into town twice a week. While it is not uncommon that he is late, some are starting to worry.
After arriving at the cave, the Hero will find that the cave is overrun with zombies. Erthor can be found in a back area of the cave set up as his bedroom. He refuses to leave until the zombies are dealt with and he is free to leave. He will ask for an escort back to Skingrad, but this can be rejected and he can head home without consequence. Either way, after he speaks to Adrienne, he will gather up some things and return to his normal life in the cave.
|"You... how did you get in here? Are those horrible creatures gone?"|
|"I'm not going anywhere until they're gone! Horrible things!"|
|"Are the creatures gone? I want to get out of here. I've been trapped for days!"|
|"I don't dare move a muscle until they're all dispatched!"|
|"I hope we'll get to Skingrad soon. I've had enough of the wilderness for now."|
|"Oh, thank you. You're just too kind."|
|"Oh. Well, I guess I can do that. I'll see you there, then... I hope."|
- Erthor is marked as essential until he is returned to the Guild hall. This means that, like Guilbert and Reynald Jemane, he can be used as a follower until he is taken home. The catch is that progression in the Mages Guild is limited.
- It is not explained why there were zombies in his cave, despite the guild's ban on Necromancy.