So this is not some copy paste, I have written this by knowledge, and made pictures for a better understanding of the fight. I hope some of you find it easier than watching a video where you can't fast-forward.
Phase 1 of Lich King encounter is fairly simple.
Things you should look out for:
What helps this fight is knowing...
-Who the add tank is
-Where the group is
-Percentage of Lich King
Healers will need to watch out for a few things...
-Infest is an AoE effect that affects the entire raid. If people are not above 90% after this happens, it stacks and cannot be dispelled until they are topped off.
Necrotic Plague is a DISEASE that will be a major mechanic to this phase.
It is simple, just when someone gets the disease, they will need to run to the add tank, and a cleanse will be used on the infected target. You have 5 seconds to do this or you will take 50,000 damage.
This will then jump to the adds or the other tank, thus reducing the damage the Lich King deals.
Keep doing this for phase 1 and you should get through it easily.
The add tank will need to pick up the adds that spawn, especially the Shambling Horrors, as necrotic plague will be needed to kill them (and they hurt).
Hunters or rogues should MD/Tricks to the add tank to help out. The ghouls must also be taken by the tank as they will put a little problem on the healers if they attack dps.
At 70%, the boss will run to the center and start doing a nova spell called Remorseless Winter.
This is an AoE that will rape you. So at 72% everyone should be ready to get to the outside edges.
What you do here is when he hits 70%, everyone should run to the outside edges to avoid the AoE.
Transition Phase 1.5 (60 seconds)
Things you want to look out for:
-Raging Spirits (spawned every 20 on ten, every 15 on 25)
-Soul Shriek (silence)
-Ice Spheres (hunters)
-Adds from Phase 1
-Remorseless Winter (LK AoE)
If the adds from phase 1 are still alive, just kite them away from the raid on the outside ledges. Let Necrotic Plague kill them.
The ranged and casters should spread out from eachother but stay on the outside edges.
The hunters main job here is to kill the Ice Spheres that spawn and make sure none touch anyone. These Ice Spheres will knock off their target (represented by a blue channeled line).
There will be Raging Spirits spawned on a random raid member, and it is the tank that tanks the boss's duty to get aggro on them and face them away from the raid.
The reason we face them away is because of Soul Shriek, which does a hefty amount of aoe damage in a cone effect. Do not stand in front of them if you aren't tanking.
The adds (shamblings) should be down by now and you might be on your last Raging Spirit.
After the 60 seconds are up, you'll notice that LK stopped channeling, and the ground is shaking. Quick! Get back on to the platform!
*The outer ring crumbles as you reach the platform... the Lich King chuckles at the demise his victims*
Make sure if there are any Raging Spirits up still, kill them ASAP, away from the raid.
If there are any ice spheres alive, please kill them before they contact the target, as this knocks people off.
Two new mechanics will be introduced in Phase 2, they are:
There will be no more Shambling Horrors or Necrotic Plague
Warlocks have a great role during phase 2. They can:
-Eliminate the need for a single Val'kyr focus.
-Defile will not be important if placed on them.
Warlocks: Stand out on the edge, with a demonic circle by you at ALL times. When you need to move, move your demonic circle.
When a Val'kyr picks you up, start spamming your teleport to circle ability. This will eliminate the need to kill that single val'kyr.
Everyone that is not a warlock will stack in the middle.
Defile is a spell that has an AoE effect. Everytime it deals damage, it's radius grows bigger. What you want to do is to spread out from the center if Val'kyrs are next, and regroup when its over.
"The Lich King starts casting Defile." is the emote shown when it goes out.
Val'kyrs, or Valks, will spawn (1 in 10, 3 in 25) and what this does is that the Val'kyr will drag the victim off the ledge slowly and drop them, preventing them from being rezzed, or any chance of survival. The DPS job is to DPS it down as fast as you can, so you can save that person and also get back to the boss.
In 10 man, set all your dps on the Valks, but on 25, split your dps up into 3 groups to kill the Valks.
Watch your DBM timers carefully. See which one comes first, Val'kyr or Defile. If it's Defile, spread out immediately from the center and everyone else and quickly collapse when its over.
If Valks are first, and Defile following a few seconds later, make sure that no one is behind the Valk. Ranged, use slows and stuns if necessary. What this does is prevents Defile being laid behind a Valk, preventing melee from helping.
When the Defile is being cast, spread out, then rush for the Val'kyr.
What you do is play WoW in windowed mode.
If you happen to get thrown off, as soon as you are dropping, right click the window title of WoW and HOLD it down until the raid leader announces in vent or something that it is Phase 2.5 (Transition 2)
This has been confirmed, and it doesn't hurt to do. So do this to prevent yourself from dying.
Now you should drag the boss over to the edge and dps him as hard as you can. Everyone should be there, including the locks. At 40% he enter's phase 2.5 (transition 2) and he will then again, run to the center.
The outer edges will reappear, and you should not jump too early, in case of falling through before it appears. But as soon as you can, jump on because he will cast Remorseless Winter.
Phase 2.5 (60 seconds) Transition 2
Raging Spirits will then spawn again, and hunters should kill the spheres. This is the ideal time to pop heroism/bloodlust as you will need to get the raging spirits down in time before phase 3. You may have one still alive during Phase 3, so kill this. Pretty much the same as the first transition phase.
You will encounter 2 new mechanics to the fight:
The Val'kyrs will not be present in this phase.
He will not cast Infest anymore.
Defile still exists, but this will be much easier to handle.
You will tank him where the red dot is, and will be kiting along the red line when necessary.
Vile Spirits are little ghost spirits that spawn when The Lich King channels it. A swarm of them spawn on top of him, this is where you will kite the boss, and the raid will go to the other side and spread out.
It is a very bad idea to kill these since it will consume a lot of time and if you get more than one and aren't a tank, this could result in a death. It's usually better to spread out and let them come.
If you are a class with taunt, you may use it for this, to minimize raid damage. Tanks be wary that this helps and pallies can use the Righteous Defense to soak up 3 ghosts.
The kiting process: You want to go around the big ring in the middle to the side opposite so it is a bit easier to spread out and ghosts will scatter more. This helps minimize raid damage.
It is useless to even try dpsing them down, as it will consume too much time.
Defile is still an issue here, so if you are already spread out for Vile Spirits, you should be spread out for Defile.
The Lich King will cast Harvest Soul on a random raid member throughout phase 3. Healers must keep this person alive or he will enter a soft enrage for 15 seconds I believe (which will most definitely wipe you.
Those that survive Harvest Soul, will enter the Frostmourne. When in here, you can see Terenas Menthil fighting a Spirit Warden. You need to help him out, by either healing him or attacking the Warden. Once the Warden is defeated, you will be erleased from the Frostmourne.
Once you reach 10%, you will notice that you wiped... wait? RP is still going on, whats going on? The DBM timer has the timer "Roleplay" heh, and when it's done, you'll know.
You have downed the Lich King if you got here, I don't want to spoil the rest.
Grats. Enjoy wiping on Heroic Gunship now.