The Siege of Crägholdt

Approach two mercenaries and defeat them.

To the east, find a tent with a level 14 locked chest and a sleeping orlan with the key. The chest contains coin and Camping Supplies. Defeat patrolling mercenaries.

Proceed east to the Training Grounds and defeat the large mercenary group. Open the trapped (level 14) and locked (level 15) chest for the Sentinel's Girdle. If the lock cannot be picked, the key is found later.

Search the table in the nearby Command Tent for an Unsigned Letter to update your quest.

Continue east to a cave entrance. Inside, face four Void Seers and two Steelspine Maguses, who will be joined by an Ancient Death Guard. Gather minor loot from dead besiegers and stashes. The passage the Ancient Death Guard emerged from is blocked.

Return to the cave entrance and head north, defeating a mercenary group.

When you see the next group, use a ranged attack to pull them towards you. Defeat most enemies before the ogre Crothar joins. Focus on Brawlers.

Continue north to find Commander Baelorin and his mercenary group. Violence is inevitable.

Prioritize defeating the Warpriest, then engage the rest. The fight is easier than the one against Crothar. Loot Baelorin's unique armor, The Golden Scales. The Small Bronze Key dropped by Baelorin unlocks the chest for the Sentinel's Girdle if it wasn't opened earlier.

Head east up a slope, avoiding a level 11 trap and two durable Alguls. Traverse the ruined courtyard past the fountain and up steps to Crägholdt. Be cautious of Ancient Death Guards; more than one or two can be troublesome. Use Prayer Against Fear to counter their debilitating aura.

Descend into the keep's lower level.

Near the stairs, interact with a floor-to-ceiling bookshelf. The first search yields a Battle-worn Grimoire. Subsequent searches offer minor loot or nothing. Grab a scroll from a nearby table.

As you move south down a passageway, a Thrall Assassin will direct you to Tanoss's laboratory.

In Tanoss's laboratory, you learn that each of Concelhaut's apprentices holds a piece of a key to his study. Tanoss offers his key piece if you kill his three rivals. Agree to his terms for now.

Backtrack to the entrance and enter the first door on the right to Uariki's laboratory. A trapped (level 13) and locked (level 12) casket contains coin. A hidden floor stash holds 3 Durgan Iron Ingots. Speak to Uariki and agree to help her for her key piece, plus extra rewards.

Return to the corridor and enter the next door on the right to Pelden's laboratory.

After questioning Pelden, he becomes hostile when you mention his key piece. Defeat Pelden before the Alguls. Loot his remains for his grimoire and minor items, including Pelden's Note, which is his key piece.

The locked (level 10) chest next to Pelden's desk contains a Rugged Wilderness Hat and Glanfathan Stalking Boots. Search the desk for Pelden's Research Notes (flavor text).

In the corridor, open the locked (level 8) door opposite Tanoss's lab. This will aggro nearby Void Seers. Have most of your party stand back and send one person to open the door, as there is an undetectable Chain Lightning trap. A Mechanics specialist should enter alone.

Inside, there are two trapped and locked chests. The smaller chest (level 10 trap, level 8 lock) contains the unique Last Tower shield and an Iridescent Scarab Figurine. The larger chest (level 14 trap, level 12 lock) contains assorted rare gems. If the trap cannot be disarmed, trigger it and retreat to minimize damage. Two other containers hold gems, including ample Adra Ban.

Enter Sabel's laboratory through the door opposite Tanoss's lab. Sabel is easily provoked, and the challenge comes from her companions.