This is the hardest part of this quest for many people. Any group of Malus Shreth may spawn the corpse you need, as long as it's not a single shreth. Look for spawns of 2 or 3 together. Once you kill them, another shreth or two will spawn, then 2-4 minutes later a corpse appears. Ignore the corpses named "corpse" and seek of new group of Malus Shreth if it appears. If the corpse is named "Shreth Gnawed Corpse," you've hit the jackpot! Loot the Crest and the Excavation Directions from it. The Shreth Gnawed Corpse may be camped for multiple Crests; they will respawn after anywhere from 10 to 20 minutes.

Reported spawn locations near the tower: 22.1N, 14.0W, 22.3N, 14.6W, 20.5N, 9.7W (use the Sanai or Embara settlement portals from Zaikhal at 12.7N, 1.7W to land close to the general spawn area).

Rumor: Excavation Directions

Once you have your crest, head to the Decrepit Tower at at 23.8N, 12.2W (Levels 40+).

Map: Decrepit Tower
Creatures: Crazed Zharalim, Demented Zharalim, Maddened Zharalim, Rayssid Ibn Alhath, Rheth Al'Thok, Tiyol Ibn Yufaj, Shadow Sprite, Small Shadow Child, Shadow Child, Shadow, Shadow Lieutenant, Umbris Shadow, Panumbris Shadow

Reaching it is tricky! You'll need to find the pass up the mountain at 25.8N, 14.5W. Cross the bridge to the tower, climb the broken stairs, then jump inside. You'll be greeted by Yalik Ibn Ujsef, Apprentice Zharalim.

Yalik Ibn Ujsef tells you, "Finally! People! People who aren't crazed!"
Yalik Ibn Ujsef tells you, "Don't look at me like I'm the crazy one. It's all those down below who have gone raving mad! Can you help them?"
Yalik Ibn Ujsef tells you, "Wait, you don't look like a Zharalim. Let me see your emblem! No emblem? Then I'm afraid I cannot let you pass. I am not about to let more people fall to the madness of this tower!"
Yalik Ibn Ujsef tells you, "If you see any of my brethren in the wilds, be wary of them. Chances are they are maddened by whatever is in the depths of this place. I fear that in that maddened state, they may have fallen prey to some beast. Shreth are all too common in this region."

You give Yalik Ibn Ujsef Crest of the Shagar Zharala.
Yalik Ibn Ujsef tells you, "Thank you! As I promised, here is the key. Use it well."
Yalik Ibn Ujsef gives you Skeleton Key.
Yalik Ibn Ujsef tells you, "Beyond the door are a series of levers. Once you pass through the gate they bar, you may not be able to return here, so please prepare first."
Yalik Ibn Ujsef tells you, "Also, if you happen to find my master in the depths, please let him know I am safe and continuing my duty up here."

Give Yalik Ibn Ujsef the crest and he'll give you a Skeleton Key (3 uses) in return. Find the button on the wall next to Yalik, use it, then use the key on the door opposite Yalik to enter the dungeon. To the north you'll find a series of 6 rooms and to the west you'll find another locked door. The 6 rooms have a series of doors and triggers you must push in a specific order to open the wooden door.

The button next to Yalik should have opened the door to the NE room. The button inside opens the SW door. The order for the next 4 doors will be E (middle), NW, W (middle), SE. You'll need to use your [ and ] keys to locate the buttons; some of them are artfully hidden behind tapestries and wall hangings or obscured by objects in the room!

Head through the now opened door to the west and hug the left wall, ignoring any of the side passages. Once you've crossed two bridges, keep to the right and head down a ramp. At the bottom of the ramp you'll go through 3 doors, then make a left. The Zharalim Master's Journal spawns on the floor in this area.

Text: Zharalim Master's Journal

Head back to the passage you were in before you took the left into the Journal area. Continue hugging the right wall until you go down another ramp. In the hallway that splits off to the left, pull the lever, continue west and follow the corridor and it heads back east over 2 more bridges. As you head north, you'll find another locked door. The lever to open it is behind some tapestries in a small room down the west hallway.

You'll now be on a catwalk area overlooking a room with some large stone heads. Before jumping down, locate the two levers in alcoves off the catwalk: one to the north and one to the south. These levers open doors to more lever rooms below (again one to the north and one to the south). Pull the upper levers, jump down, then pull the levers in the lower rooms. Head through the now open passages to the west.

Note: before moving forward, make sure everyone grabs the 2nd journal, spawning on the floor of the stone head room.

Text: Zharalim Foreman's Journal

Follow the passage west until you reach a large open room with two passages heading down. Either of them will get you to the next level. You'll next need to trigger a floor panel in a small flaming room. If you took the east passage down from the large room the pressure plate room will be straight ahead. If you took the west, it will be to your left. The pressure plate in the NW corner of the room opens a door down the west hallway.

Once through the door, you'll be climbing up more broken stairs. You'll need to make a small jump over a missing section and parts of it will be invisible. Once at the top, follow the passage to a spiral staircase. The next spiral staircase (to your immediate left) is blocked by, yes, another locked door! To open this door, head all the way down the hall to the north. You'll be pulling 2 of the 13 levers in this room, the first on the right (to open the door on the other side of the spiral staircase), and the third from the left on the west wall (or levers 8 &13 if you're counting from left to right). Watch out for the dispel traps! You can hug the wall from the right side to avoid it.

Another small room between your location and staircase should now be open. Pull the lever inside and the spiral staircase door will open.

Follow it down to the final room where you'll battle 3 named Zharalim: Rayssid Ibn Alhath, Rheth Al'Thok, and Tiyol Ibn Yufaj. Each drops about 8 tassels (2 week timer). When everyone in your party has all 3 tassels, take the exit portal nearby.

Note: This area also contains a Festival Stone and an Altar of Bael'Zharon!

If you give the tassels to Yalik, he returns them to you and directs you back to Ufet, Prophet of Blades. Return to Zaikhal and give the tassels to Ufet for your reward!

You allow Yalik Ibn Ujsef to examine your Woven Tassel of Discord.
Yalik Ibn Ujsef tells you, "This came from the garb worn by one of the traitors? I have no need for it and I have nothing to reward you for defeating them. My apologies. Perhaps someone else affiliated with the Shagar Zharala can given you a prize worthy of your efforts."

You give Ufet, Prophet of Blades Woven Tassel of Far Sight.
Ufet, Prophet of Blades tells you, "This came from the Shadow's Garb worn by Rayssid Ibn Alhath? Sadly I know little of the man save for his affinity for ranged weapons."
Ufet, Prophet of Blades tells you, "It seems only fitting that the reward I give you should reflect that. Take this periapt. May it help guide your shots with accuracy and swiftness."
Ufet, Prophet of Blades gives you Periapt of Endless Sight.

You give Ufet, Prophet of Blades Woven Tassel of Sound Mind.
Ufet, Prophet of Blades tells you, "You say Rheth Al' Thok wore this upon his Shadow's Garb? He was a bright man, poised to enter the ranks of the Zaikhal Arcanum. Well... that was before my compatriots offered him a place within our ranks. A shame that he was so easily enticed."
Ufet, Prophet of Blades tells you, "Since he joined the ranks of the Zharalim, he was striving to obtain the Shagraka- the casting focus used by many of the Zharalim's sorcerers."
Ufet, Prophet of Blades tells you, "As he is no longer with us, the focus reserved for his use shall be passed on to you."
Ufet, Prophet of Blades gives you Shagraka.

You give Ufet, Prophet of Blades Woven Tassel of Discord.
Ufet, Prophet of Blades tells you, "Ah, Tiyol's tassel, correct? I had no liking for that contemptuous man. In fact, it would not surprise me at all if he was the first to fall under the sway of the Raven Hand."
Ufet, Prophet of Blades tells you, "You did the world a great justice by defeating him. And since he was such a vile man, I have no qualms about giving out his belongings."
Ufet, Prophet of Blades tells you, "Before the group left for the library, many of them entrusted some of their belongings to my care. Primarily items that would be of no use to them in the grasslands and forests north ofhere."
Ufet, Prophet of Blades tells you, "Tiyol left this Cowl. Here, take it. I am glad to be rid of his belongings. Surely you will put the Cowl to a more appropriate use."
Ufet, Prophet of Blades gives you Cowl of the Sand.

The Cowl of the Sand casts Finesse (+8 to coord) which surpasses Moderate coordination (+10 to coord). See known issues about the spells on these items.

Cowl of the Sand cast Zeal on you
Cowl of the Sand cast Thew on you
Cowl of the Sand cast Finesse on you, surpassing Moderate Coordination
Shagraka cast Shade of the Oasis on you
Shagraka cast Water of the Oasis on you
Shagraka cast Fruit of the Oasis on you
Periapt of Endless Sight cast Raptor's Sight on you
Periapt of Endless Sight cast Far Sight on you
Periapt of Endless Sight cast Endless Sight on you
Periapt of Endless Sight cast Finesse on you, surpassing Finesse

Other reported rewards:

Singularity Key (un-carved)
Sturdy Steel Key
MMD (250,000) Trade Note
Platinum Golem Heart
Pyreal Bar
Pyreal Golem Heart
Ingredients for Treated Healing Kits
--(10 Treated Hyssop, 10 Bandages, 10 Mandrake)
10 High Stakes Gambling Tokens
3 Sturdy Steel Keys