Sammath Gul
Sammath Gul, a six person instance. When you first run in, there's going to be a few mobs. You probably won't notice this, but there's going to be this guy staring down at you from a ledge and laughing. This guy isn't even a boss, but he's the first tough thing you'll face. Why? Because he's going to keep sending mobs at you and he's (sooner or later) going to put a buff on the mobs that make them immune to damage (instead, all damage will be redirected to him). There are two staircases in front of you and you can go up either one to get to his wide balcony.
Now, if you go in to the left, pull a small group, then the small group, then slowly fight your way up the stairs there, you won't get much aggro. Perhaps no more than 6 guys at once? Or, you go rush to the boss and fight a monster truck load of guys all at once. I'm actually not sure where that huge load of guys came from, but you don't have to fight everyone all at once.
So, after this guy, you're now free to move on to the rest of the instance. Here and there, there are little bone piles that, if you walk over them will spawn a spirit (like in Fornost, but all the spirits are evil wicked spirits). Make a note of these guys, because when you fight Gorothul hard mode is to not kill those bone-pile spirits if you spawn any. You can tell the difference because right now they're called Guldur Spirits and in the Gorothul fight they're called Ancient Fell Spirits.
So, there are going to be a few more small sets of guys, basically three people, like in the Grand Stairs instance, but one of them will throw up that "untouchable" buff on the others (so attack them to damage him). There's also a patrolling guard and brute that, after about half an hour or so, will respawn, so watch out for them both initially and if someone is running back through the instance later. Also, watch out for the bone piles. And the odd loremasters, they're a royal pain -- I'll talk about them in the next big room, the first boss. Also, watch out for the sorcerers.
The First Boss
There are four groups in this room. DO NOT GO IN. Brutes, Guards, and something new, Loremasters (well, newish). They have this fire thing where they punt you back and throw down flame near them (the beer-brawl is great training for this sort of thing -- it's so helpful to have some good experience in turning around in mid air and guiding where you're going to land). Try to mez them somehow and take them down last. Believe me, you don't want them to get that untouchable buff on them (or, if they do, you want it to happen while they're safely mezzed away). Once you finish mezz-pulling or whatever (riddling?), you're ready for the boss. You might not have noticed him because he's laying down on the central pillar. Start to fight him. He can throw out one of two effects -- one has a gren eye, the other doesn't (he also says different things for each effect which I'll explain in turn). It's very important that people are watching out for what's happening -- you cannot go afk in this fight or multi box (not that I've ever had anyone do that yet, but still I've been in weirder groups in the past).
1 green eye means you have to run the heck away from everyone -- go far, far away, because this spreading fire is about to go off and it'll spread from person to person and back to the original person and stun you all. Do not mess with it, do not back away, turn and run like Freddy Kruger is after you. After it goes off, feel free to come back. Pull the camera back above your head, the eye really doesn't last long and then you can run back.
When he says something about feeling the burn, you have to group up tightly. It's going to put out some damage and drop some fire -- the damage will be shared amongst everyone and the fire will harmlessly pass away. If you're not close, the wave of fire will hit you and rebound and everyone will die.
You must have situational awareness (or be listening to someone with situational awareness, as you cannot mess around with this).
Once you get him down to around 28-30k, he stops with the eyes and fire starts erupting from the grates in the floor, just like the 2nd Hall of Crafting boss. Pull him to a front corner by the door you came in by corner before this and when you see the fire, go to the opposite corner of the room. Watch to see which way the fire is moving, then start running in the opposite direction as the fire will start to sweep around the room (like in the Forges). After this, he dies and the chest is yours. Everyone should loot it to get their Medallion of Mirkwood. Don't go Master Looter -- most of the stuff is just ixp relics and runes. With only one item, go read it, click roll or pass, then click roll on everything else.
Some more mobs like the first ones you fought, watch out for the bone piles, then the second boss's room.
The Second Boss
The pattern is below but if you do not want to bother with it, 2nd phase of fight, run to top left pillar, furthers away from wall you start at on the left.
You'll notice that this boss's room is open to the sky. The first fight is pretty traditional. He has a good frontal AoE attack, so everyone should be behind him and he can punt people in front of him, so tank him with your back to the high solid cement wall in the middle, so you don't get knocked over the wall around this area. It's basically just like the final Caerog fight in the Water-wheel instance, but the boss mob is smaller size and he doesn't run away to heal, but it's about the same as every time he punts someone, he's going to wipe his aggro and go attack whoever he wants. Hold your damage at that point for a moment, if you have a tank, then once aggro is on whoever it's supposed to be on, go to town. That's the first part of the fight. Then the second part starts and things start to get tough. He's going to call lightning down in four waves. Ranged damage is key here. You do get a brief moment to melee him between sets of waves and during the first wave and FM's can safely be triggered at this point. But it's mostly going to be ranged damage. The lightning attacks will all be vertical strikes from the heavens and being near where they hit ground will hurt. A lot.
The first attack will be a diamond attack -- from him, basically, to the big jar over by the far door, to the cement thing in the back, to the jar by the near door, to him. Stand in the middle.
The second attack will be a fan attack. It'll all hit in front of him, so anyone meleeing him (possibly everyone if you're doing a RRRYYY Tramp of Doom conjuction or YYYY, depending on how many people are alive) had better be somewhere else or they're going to suddenly take a lot of damage. Stand right by the big jar by the door you came in by.
The third attack will be a triangle attack. Down the middle, across, then back up to him. Stand by that jar, then move to the middle of the room when it's safe. Then get the heck out of there because...
The fourth attack is a heart attack (heh). Down the sides, wrapping around, then crossing in the middle. Stand in the middle of the top part of the heart.
Here's a picture. I drew a blue circle for where I reccomend to stand.
Click to enlarge
So, after that you're good. You cannot loot the next chest yet, though, you have a small group to go through. Be very, very careful looting the chest, there's another double group after this. Again, everyone should loot the chest. So, then we get to the third boss.
The Third Boss
Gorothul is a man. The gate to this "room" is actually at the top of the first set of stairs that lead up to him, so don't stand back by the door when he's triggered. The bone piles in this room won't spawn spirits until his fight is triggered. Once he's triggered, if you don't want hard mode, feel free to trigger and kill the spirits. Gorothul has two ghost loremasters on a timer. You can kill them or cc them and wait for them to despawn -- after a couple minutes they'll come back. If you kill them you'll have a bit longer until they respawn, but there will be less dps on the boss.
The boss fears people, which might cause a person to summon an ancient fell spirit by running over the pile, the boss can also punt people. Every person I talk with who has beaten this says that constant never ending interrupts are the key to stopping these. However, all of our interrupts have been nerfed. Champions are longer now, Wardens can only interrupt on Wall of Steel and Onslaught if the first attack in the series doesn't miss and all of our interrupts do jack all for damage. Also, some of his animations are short, so you need a couple people just spamming interrupts on him. Faster than an interrupt every 3-4 seconds. You can interrupt everything but his fears. However, when feared, spam /follow. Type: /shortcut ## /follow (where ## is the hotbar slot), then click-spam it while feared, you won't run as far and it's not like you have anything else to do.
Then there's a second stage of the fight, where adds will come and healing generates more aggro. So you basically need someone like the 16th Hall to kite the adds (cough*warden*cough, although a captain does an ok job of this, since your warden may be busy tanking and/or interrupting -- I tried this and without a loremaster or captain I just ran out of power too darn fast and as soon as I stopped interrupting he started nonstop punting). Or tank them all, leach morale. A champs AoE is great for burning these mobs down if they're all around Gorothul. You can also have a guardian shield wall the healer, then have the healer pour morale into the guardian and ignore the rest of the party (which may or may not be good) while the guard tanks Gorothul and the adds. There's a number of different strategies for this. Good luck. This is where the minstrel has to run up by Gorothul, as it's just too difficult to find someone.
Then there's a couple more bone piles, a room with some adds in it, then the last boss (who's easy, so I hear).
The final boss
This one is a giant green spirit. He does all shadow damage and he has two pits in his room. If you fall in a pit, you die from misadventure. Other than that, burn him down.