|# of Zones||3|
|Respawn Time||10 days or 30 days|
|Warlocks, Frostbite Spiders, Vampires, Wolves, Skeleton, Flame Atronachs, The Caller, Orthorn|
|The Doors of Oblivion
A Hypothetical Treachery
Spell Tome: Sparks
|Console Location Code(s)|
|FellglowKeepExterior01, FellglowKeepExterior02, FellglowKeep01, FellglowKeep02, FellglowKeep03|
|# of Alchemy Labs||1|
|# of Arcane Enchanters||1|
|# of Forges/Anvils||1|
|# of Workbenches||1|
The fort consists of three sections: Fellglow Keep Dungeons, Fellglow Keep, and Fellglow Keep Ritual Chamber. Part of Fellglow Keep and all of Fellglow Keep Ritual Chamber are only accessible during the Hitting the Books quest. The keep can be reached by following a path from the northern Valtheim Tower.
 Related Quests
- Arniel's Endeavor
- Hitting the Books: Find the books needed to identify the artifact found in Saarthal.
- No Stone Unturned: Find the 24 gems to restore the Crown of Barenziah.
 Zone 1: Fellglow Keep Dungeons
The first room in the dungeons is a partially flooded round room containing two skeevers, which then exits through a passage with a couple of bear traps. In the next room there is an ice mage with a couple of frostbite spiders. The southeast exit from the room leads to a corridor that branches in two directions, with a pressure plate trap at the junction. The southeast branch of the corridor leads to a small room with an adept-locked chest and some scattered loot.
The northeast branch of the corridor contains an elemental rune trap (Note: this rune has been reported to be invisible at times, so tread carefully; additionally, if you trigger it from a distance, it may alert the mage in the next room). Beyond the trap, you will find a room with four locked cages and a mage. Three of the cages hold captive vampires, which, if you unlock the cage doors, will go to the next room and attack the group of mages there that have been performing dissections on a pair of master vampires and a Khajiit. The vampires will then leave the dungeon without attacking you (unless you attack them first).
The next room is a circular area containing one mage and three cages: one empty, one holding Orthorn, and one holding a pair of wolves. The mage may release the wolves to fight for him, if given the opportunity. Orthorn will ask to be freed, and offer to follow you. The cage locks are controlled by the three levers in the middle of the room. The stairs to the northwest lead to a key-locked door to Fellglow Keep.
There is an adept-locked wooden door to the left of the entrance that leads you to this room, holding an apprentice-locked chest and some additional loot. The other unlocked wooden door from this room leads to a corridor and, eventually, a training room where three mages are testing their spells against targets. One of the targets is a leveled vampire, but there is no way to release her.
Next, you will reach a long rectangular room with a few mages and a group of skeletons. In the last casket on the right before the end of the room is a random soul gem. At the other end of the room you will find a small caved-in area with a chest and some additional loot, and a set of stairs up to Fellglow Keep (this time through an unlocked door).
 Zone 2: Fellglow Keep
Assuming you enter the keep through the unlocked door at the eastern end of the Fellglow Keep Dungeons, the first room you encounter holds a couple of mages ready to fight. They may open the door to the next room and call for reinforcement (another mage). You will find a copy of the Conjuration skill book The Doors of Oblivion on a podium in the first room, as well as an unlocked chest. A shrine of Talos lies on the floor next to a broken altar in front of a damaged statue of Talos. Also, there is a half-buried glass sword to the left of the broken statue.
The passage continues to your left, leading to one of the key-locked doors to Fellglow Keep Dungeons, and a larger room with a group of mages and a flame atronach. This is a two-level room, with a set of stairs in the middle. You enter from the lower end, where you can also find a key-locked door to the outside, and a door to the living quarters of another pair of mages. Upstairs, you will find a door and two passages. The door is barred from the other side.
One passage (facing southwest) leads to a room with a workbench, an alchemy lab, and an arcane enchanter. The room also holds three quicksilver ingots and an unusual gem (related to the No Stone Unturned quest). There is also a black soul gem in the bookshelf in this room.
The other passage, facing northeast, leads to a library (Orthorn will warn you, if he is with you). One mage can be found in the center of this circular room, surrounded by bookshelves. Most of the books in the library are ruined, but you can find a Spell Tome: Sparks on a shelf on the opposite side of the way you entered the room, and a copy of the Destruction skill book A Hypothetical Treachery on a table in the center area, among others.
Follow the stairs out of the library to reach an L-shaped room with four doors. A flame atronach will be patrolling in front of the two doors farther from the side you enter the room, ready to attack you, and alerting a mage behind one of the doors (the second-closest to your entryway) in the process. The mage carries a Fellglow Keep key. The first door closest to your entryway leads to a small living quarters with a chest; similar items are found behind the second door. The last two doors are next to each other. The one on the right is locked (Adept-level, but can be opened with the Fellglow Keep Key), and leads to a room with a shrine of Julianos, and beyond that another living quarters with an adept-locked chest.
The last door from the L-shaped room opens to a set of curved stairs leading up to a couple of bookshelves (with useful potions and scrolls), and a door to the Fellglow Keep Ritual Chamber.
 Zone 3: Fellglow Keep Ritual Chamber
As soon as you enter this area, The Caller will detect you and initiate a dialogue. She is the leader of the group of renegade mages, and is quite upset over your presence and the destruction you have caused. She also possesses the three books that you require for the Hitting the Books quest that are located within this room. Your options are essentially:
- Fight The Caller: either through certain dialogue options, by attacking her, or by picking up one of the quest books;
- Trade the books for Orthorn: through some dialogue options, The Caller will offer the books in exchange for your companion; if you accept, Orthorn will walk back to the keep, while you may pick up the books and leave without a fight. If Orthorn is not with you, and you tell her "Maybe we can come to an arrangement," she replies that you have nothing she is interested in.
- Persuade her to give you the books: She will then let you pick up the books without fighting;
- If you successfully persuade The Caller, Orthorn will act as if you accepted The Caller's trade, saying "How could you leave me here?" and walking off into the keep.
After the fight, Orthorn may tell you he will stay away from the College for a while, and leave you. The door behind The Caller holds a chest and other valuable items, as well as a shortcut back to Fellglow Keep.
- The room across from The Caller can't be opened unless you have the Fellglow Ritual Chamber Key. This key can't be pickpocketed and can only be obtained by killing The Caller or by using the Wax Key perk on the vampires' cells in Fellglow Keep Dungeons. (However, the door bar after exiting through the trapdoor can be lifted from the opposite side, enabling access to the treasure room before even meeting The Caller.)
- A copy of Boethiah's Proving, which starts the quest Boethiah's Calling, can be found in the large circular storeroom (the room with all the bookshelves). It is on a shelf immediately in front of the doorway which enters the room from the north. This book only shows up if your character's level is 30 or higher.
- As soon as you turn in the quest Hitting the Books, the upper part of the castle will be blocked, and more enemies will have spawned. If entered through the main entrance to Fellglow Keep (after you obtained the key) you end up directly in the living quarters. Right up the stairs there is the room to the right where some smithing equipment and an enchanter is found. The other two passages to the upper part of the castle are blocked by collapsed ceilings.
- You cannot clear this location during Hitting the Books since the boss is disabled for the duration of the quest.
- If you clear out Fellglow Keep before you accept the quest Hitting the Books, during the mission the game will crash when trying to go in the dungeon.