The Sleeper Amulet
Quest giver: automatically after killing all cultists [Thorniara - Temple District]
Description: Wait for mages from Tooshoo and get close to them #1 (M12B, 42). During the conversation with Daranis #2 you will know that Merdarion, Ningal or Milten will help you with the barrier. I advise you to do the quests for all three mages and then ask one of them for help.
Option 1 - Side with MERDARION:
Merdarion will ask you to bring him three mana runes. To find the first one, you have to get back to the harbor. When you will be there go to the lighthouse #1 #2 (M12B, 11).
Go upstairs and the rune will be located on the wall #1. For the second rune go to the bastion located near the arena #2. It is located east of the fortress (M12B, 43).
Examine the wall. Rune will be lying in the place where you will be able to see the top of the tower #1 (M12B, 36). To find the third rune you have to go into the fortress (M12B, 26). Go on the level where the throne hall. Go to the opposite side and use the passage where some ladies are standing #2.
You have to get on the small balcony #1. You have to see the bazaar from above and the rune will be in front of you #2 (M12B, 44). Now you can go to Merdarion (M12B, 42) to give him all items.
Option 2 - Side with NINGAL:
Ningal will ask you to kill 5 Ahn'Bael (M12B, 45) and bring him six hearts. You can attacks this monsters in any sequence (they are marked on the map). You have to localize the enemy #1 and defeat it in a fight #2. After the battle take its heart. They are quite simple so you shouldn't have problems with them.
The only difficult Ahn'Bael is located in the wealthy district #1 (M12B, 15). Use the passage leading to the canals #2 (M12B, 20).
When you will be underground turn left #1 and use the gate where you had spoken with stal Daranis. Ahn'Bael is located near the exit (M12B, 40) and the catacomb entrance #2 (M12B, 41). After killing all Ahn'Baels return to Ningal (M12B, 42) and give him these items.