This walkthrough has most of the info in it correct. It was formed from memory, looking at logs and talking with others who run it. They may be some errors in it and there are always more methods to fighting than the ones presented.

Group Makeup: This is one makeup that works well
Healer: Minstrel/RK
CC: Ancient Master LM/Burglar (LMs want to use your tiger on non boss fights and bear on boss fights with shatter arms, eagle can be handy for the 2nd boss for the power regen)
Kiter: Warden/Captain
Ranged: RK/Hunter
Melee: Guard/Champion
Open Slot: Captain if a warden is the kiter else someone else handy. Champions are handy for their melee aoe and clobbers.

One ideal group is Warden, Mini, LM, RK/Hunter, Guard/Champ, Captain.
Another group: RK, Hunter, Champ, Guard, Burg, LM
Another group: Warden, Mini, LM, RK, Guard, Champ

Before getting into the walkthrough there are a few things to know about some of the mobs in this area. The ones to know about are as follows.

Brutes - These are orcs that will put up an aura around themselves that reduces the direct damage done to them by over a factor of 10. While this aura is up all damage done to any other mobs within the area of affect will be redirected at the Brute. So what you do is everone selects another foe and uses all their skills on that foe instead of the brute, aoes are very good in this instance if there are many foes protected by the brute. Then when the aura is off everyone switch to the brute and kill it. You do not want to kill the foes around the brute entirley until the brute is dead. If the brute is the only foe you have while the aura is up only use auto attacks. Brutes also havea  frontal aoe attack that does some good damage to anyone they are facing.

Sorcerors - These are men who cast shadows upon you and will give a fear affect onto someone forcing them to cower. The shadows have range from direct damage type looking a lot like an oathbreaker to a shadowed root. There is no trick to killing him.

Loremasters - These foes are just plain anoying. They have a very nasty aoe knockback that they cast. Half of the time that these are encountered you are in a ramp/stairway so if you are kicked back down it you will break your legs. This knockback is interuptable while they are casting it via clobbers, stormlore etc. To prevent this put your back to the wall and jam yourself next to the pillar making it so you can't be kicked down the ramp. The other half of the time that these are encountered you are in an area where one side of the area is a giant fence. If you get knocked over this fence you will plummet to your death. So you fight in an alcove with your back to the wall. It is best to keep these loremasters mezed while fighting the others unless there are Summoners present.

Summoners - These are relatively weak but they summon spirits that are pretty strong. Its best to have these mezed instead of the loremasters.

Fellspirits - These are summoned by stepping on or near the bonepiles. They have a ton of morale making it so at least 3 people are needed to kill them. While they are alive they will constantly summon skeletons to come after you. This includes if you all wipe while one is up it will keep summoning them sending them after you. If you get a FM on these go all yellow.

Upon entering the instance there are two routes to take stairs on the left and right. It doesn't matter which you take. I typically take the left option. Upon getting close enough a wave of mobs will be triggered, it is good to fight just at the base of the stairs. In this group will be a brute. Fight as described above in the brute explination. Once you are down to about one foe someone should run up top and pull the last group of mobs and bring them back down to you.

Next you go up the stairs and around on tables will be skulls that anyone with the 'first time through' quest will be able to get. Now you go up to the top of the ramp to the left. In this room you will have a brute and 3 summoners. It is possible to pull the brute without any of the summoners coming. You kill the brute and summoners and this room is pretty much set. You will start to encounter bonepiles in this room. These when stepped on or near will summon a fell spirit ONCE. For more explination on that see above. There are times you will want to trigger a bonepile but for the most part stay away from them they are annoying. At the base of the next ramp will be a bonepile you will want to trigger on the off chance you are knocked down.

At the top of the next ramp you will have two groups of foes and a brute who walks around. The brute can be pulled w/o either group being pulled if done right. In the right group will be a Loremaster and a Summoner. I don't recall who is in the left group I think its only summoners. Keep the LM mezed and kill the summoner then kill the lm. This room has many bone piles so watch out.

Again at the base of the next stair will be a bone pile you want to trigger and take out. Up this ramp is the first boss's chamber. You want to fight on the ramp, if you go to far into the room you will trigger the boss which you don't want to do till all the other foes in the room are dead. There are four groups of mobs the closest group on the left and right will have a Loremaster and Summoner the second group on the left and right furtherest away will have a Loremaster, Summoner and a Brute. Again take these one at a time mezing the LM and burning the rest.

Now you are upto the boss fight. Firstly stay off the metal grates entirely including the medtal outline of it. There is fire that periodically shoots up out of it and will kill you like in the Hall of Crafting. The boss has two things that he will do. First is he choses one member of the group and says 'Will you bring doom to your friends <insert name>!' and he will place a green eye on top of your head. Whoever he choses has to RUN AWAY FAST. If you are close to your group after about 3 or 4 seconds everyone in range will be dazed for 5 seconds or so. If you get dazed more than about 2 maybe 3 times the group will wipe. Someone with voicechat needs to be on eye duty to call it out as you see it in addition to people watching themselves The second thing he said is 'Can you handle the burn' at this point everyone needs to be in melee range and the Loremaster has to wait about 5 seconds and then start casting leechcraft. The boss casta a massive aoe fire attack that puts a nasty dot on everyone so the faster it is off the better, the timing takes a bit to get used to. The fight itself is a DPS race as as you fight the room will start to be engulfed in flames, these flames are an instant kill if you touch them. Most of the time the best place to fight is in the squre to the left of the first grate when you walk into the room, sometimes though the fire works differently so keep an eye out.  That is the first fight. It is possible to kill him and get wiped by the flame. That is the first fight the chest is in the hallway beyond this room. There is nothing major of value in it so most groups will roll/pass it.

Next you have a bonepile then a ramp, at the top of the ramp is a Loremaster, Brute, Sorceror combo. Noone move past the bone pile. This pile you want to trigger and take out. Next you mez the lm and burn the rest. At the top of the next ramp you will pull a Brute and a Guard. Fight as usual getting the brute down first. Now you are in the room where one side is a high fence and the other is a wall. At the far side of the room are a Summoner, 2 Loremasters I believe and a Sorceror. Everyone but the loremaster will be fighting in the 'cubby' to the left out of sight of the gate where the mobs are. The loremaster is on permamez duty on the Summoner and if he can one of the Loremasters. (for the Ancient Master Loremaster how you duo mez, blinding flash first mob, select 2nd mob and rising dawn it, keep its attention till blinding flash is useable again then mez that target, now each time blinding flash is useable you have to use it immediately on your next target to keep them down.)The mezer wants to stand away from all of the fighting so he doesn't get any knockbacks, ideal spot is hidden away from the fighting by the gate where the npcs are.

2nd boss fight room. Skirt along the left side until you get to the locked gate. This is where the first stage of this fight will take place. During the first phase the boss will say "Do not stray too far from me (name)" at this point you want to be in melee range which isn't a problem in this phase as everyone is right on top of him at the gate, There is no floating text or voice or eye, its only in the chat log. At 130k the loremaster will want to start to drain power because at 100k he goes into a drama mode where you can't attack him moving back to his alter where he stays for the rest of the fight. Everyone wants to conserve power at 130k aswell. There are two methods for the second phase of the fight first is melee second is ranged. In this phase there is lightning that will constantly rain down upon field in a pattern of sorts. If you get a direct hit its 4-5k dmg, splash dmg around it is about 1k. At the start of this phase he will do one more callout so whever he calls out if you can run upto him reguardless of what method you are using. The melee method is you run up to the boss dancing around the lightning going where it just hit basically staying out of the areas that aren't cracked on the ground. The method I currently prefer is the ranged method. In this method everyone stands at one specific spot, this spot when standing at the gate for phase 1 facing the alter is the 2nd lamp to the left. From here everyone who can range will constantly range the boss. During this phase bog lights will also spawn so everyone who isn't ranging will be taking care of them keeping them off the healer, these bog lights also root people. This chest you will want to master loot as there is jewelry that some people like.

Next trigger the bone pile near you and any in the alcove you want to fight in and burn them down. This next group has 2 summoners, brute and 2 loremasters. Cycle mez the summoners as explained earlier and everyone else fight the loremasters in the alcove with your backs to the wall. Loremaster this time there is a bone pile in the area you like to stand in so you will need to stand almost on top of where the mobs are while chain mezing.

Next is you enter a room that leads into a large hall that holds the 3rd boss. you want to fight in the small room not the hall. This group has about 6 mobs in it. 2 summoners that the lm chain mezes, summoners, maybe a loremaster, not sure about the others. everyone but the lm stays and fights in the small room before the chamber. The reason for this is in the chamber along the sides are a ton of bonepiles that you never want to touch or approach. Once all of these are down you are the third boss.

This is the hardest boss in the instance. At the top of the stairs you want to do all of your buffs, scrolls etc, short term food can wait as it can be eating in a min. once you approach the boss he will go into a drama where he stuns you and talks with Sauron for 20 seconds or so. While you are stunned you can eat your food. There are two ways to do this fight only one of which I've done. To start everyone is on the boss and they want to be between him and the throne where he first came from. This is because this boss has the lm knockback skill so you want to be knocked up hill instead of downhill, as with the lms this knockback can be prevented by a clobber or other daze. Gorothul the boss also has a fear that he casts that will force someone to cower. This boss is a two phase fight. The first phase goes until you reach 145k. During phase one you have the boss and the spawning and despanwing Loremasters and Sorcerors. If the loremaster/sorcerors are despawned at the 145k mark they will not respawn again, reguardless after the 145k mark you can kill them and they will not respawn. Throughout this fight blue spirit versions of the sorceror and loremaster will randomly spawn and then after a bit despawn and then respawn later. Sometimes its 1 and 1 sometimes its 2 of one of them. If a loremaster spawn our loremaster wants to mez this spirit. You typically don't need to hit him more than once with a mez because by the time your mez is up he will have despawned and you want your blinding flash up to use on a respawn. You need to be on top of this as its a major annoyance to the fight. Once 145k is reached this is when the Ancient Fell Spirits and Skeletons will start to spawn. The Ancient Fell Spirits once spawned will attack you for a bit and then head to Gorothul and despawn. Once they despawn Gorothul will do a group wide cower, this is able to be prevented by a conjunction if you have a burg with you. A minstrel anti-fear circle may help prevent but I'm not positive. Potions do not work to remove this fear. You want to save all yoru big attacks for the second phase because the longer phase 2 goes on the more skeletons that will be spawned. If a conjunction is ever gotten on the boss go all yellow ignore any others. guards want to keep the skill stacked on the boss that increases the % of a fm. Skeletons will also start spawning on a timer from the bone piles around the room. You must not kill the ancient fell spirits if you want to keep the Hard/Challenge mode. So the main method is to then have the warden/captain start kiting the skeletons and spirits around the room 16th hall style once they become overwhelming. These Ancient Fell Spirits have about 4.7k so they can be hit a few times just be careful with aoes around them. From here on its a matter of keeping the kiter up pulling the ads off everyone who is taking down the boss. Keeping the kiter and everyone else alive, dpsing the boss and mezing any loremasters that pop up. Its handy to put stun immunity on the kiter if you can. There is a second method to deal with the skeletons and that is to have one of the melees tank them doing massive aoes on them.

This chest tends to have good loot on it and it has a chance to spawn the symbol needed to craft lvl 65 reforged 2nd age legendary items. Now you have a ramp that goes down into another chamber. You want to fight at the top of the ramp. There will be 2 summoners and 2 LMs. the summoners get chain mezed and the lms get burned FAST. The longer this fight goes there is a timer where guards and a brute will come from below so this needs to be all killed as fast as possible, the main focus are the LMs and summoners once they are down the brute/guard ads will stop coming. Avoid all the bone piles in this room once the mobs are down. go down the ramp and step just inside the room careful not to get close to the bone pile on the right. resummon pets once inside the room to be sure they aren't trapped outside.

Now we are on the final boss. First we trigger the bone pile on the right and then leave it alone. Next everyone will run to the boss and straight up tank and spank him. There is one trick with this fight. As the fight progresses a green flame will encompass 1/4 of the room and then work its way around as 1/4 for a while then increase to 1/2 of the room and keep working around. If you go into this flame you will have your max morale reduced so stay out of it! That's the only trick to this fight once he is down go and kill the fell spirit at the bone pile. This final chest has a chance of dropping the symbol needed for LIs as well.