FML and here we go....

Imperator Mar'gok is the last encounter in the Higmaul raid.

For a more detailed view of his abilities PLEASE PLEASE PLEASE view the Dungeon Journal in-game, or FUCKING CLICK HERE to view them at WOWHEAD.

Imperator Mar'gok is a 4-phase encounter with 2 intermissions between phase 2/3 and 3/4.

The phases have "repetative" abilities from phase-to-phase, meaning they will have their normal effects (mostly) but each ability will be augmented with additional effects from phase-to-phase.

Abilities

Phase 1 (100 to 85%)

1. Mark of Chaos - Tank debuff, lasts 8 sec.  After this expires, deals massive dmg to all nearby players (not the affected tank) within 35 yards.  Tank run away from raid.
2. Accelerated Assault - Each consecutive melee attack against the same target will increase the bosses attack speed by 8% (stacks).  Tank swap, likely just swap around the same time as the MoC debuff gets applied.
3. Arcane Wrath - targets a random player and "brands" them for 4 sec.  When this expires, it will deal moderate arcane dmg and will jump to the closest person within 200 yards.  Each time this jumps, the dmg will increase by 25% and the range will decrease by 50%.  You need to get this to jump a few times(probably 3 times), then have the 4th affected player run over 25 yards (200->100->50->25) away so the debuff has no one to jump to and it just falls off.
4. Destructive Resonance - An arcane mine that lasts for 1 minute.  If triggered, will deal moderate/high dmg to all players and massive dmg to the player that triggered it.  Will also increase that persons arcane dmg taken by 45% for 1 min and stunning them for 1.5 secs each time they take arcane dmg.
5. Arcane Aberration - Summons an add that pulses mild AoE dmg to the raid.
6. Force Nova - Releases a large arcane energy wave that deals mild arcane dmg every 0.3 sec to all players within the effect.

Phase 2 (85% to 55%) - Rune of Displacement Phase, primary abilities are augmented with "Displacement" effects.

1. Arcane Wrath: Displacement - Same effects as normal, but players cannot move 10 yards from the spot they were marked.  If they do, they will be teleported BACK to their original spot
2. Destructive Resonance: Displacement - Same effects as normal, but now it grows to twice its original size over 30 secs.
3. Displacing Arcane Abberation - Same add as normal, but when it dies, it will knock back ALL players (or so says the DJ)
4. Mark of Chaos: Displacement - Normal effects, but the target (tank) is teleported to a random location
5. Force Nova: Displacement - Normal effects, but now also pushes players away (with the wave) as it expands

Intermission 1 (55%) (lasts 1 minute)

During this intermission, the boss will begin channeling a new rune to augment his abilities.  He will be immune during this time.  He will also summon 2 Gorian Warmages, and Volatile Anomalies will spawn from the rune stone every 12 sec.

Gorian Warmage - These will fixate on random players, attacking only them for 15 seconds before swapping.  They also have a Dominance Aura, which empowers all enemies within 25 yards.  Increasing dmg done, as well as melee, ranged and spell casting speed by 50%.  Will cast Nether Blast, dealing moderate dmg to any player within 5 yards of the target.  Will Slow (dispellable) random players, reducing movement, attack/spell cast speed by 50% for 45 sec.

Volatile Anomaly - Tankable.  When killed, explode for moderate arcane dmg to ALL players.

Phase 3 (55% to 25%) - Rune of Fortification phase, primary abilities lose "Displacement", but are now augmented with "Fortification" effects.

1. Arcane Wrath: Fortification - Normal effects, but the range reduction drops from 50% to 25% with each jump.
2. Destructive Resonance: Fortification - Normal effects, lasts for 2 minutes instead of 1.
3. Fortified Arcane Aberration - Adds are now immune to all CC and have 75% more health
4. Mark of Chaos: Fortification - Normal effects, target (tank) is now rooted in place
5. Force Nova: Fortification - Normal effects, however an additional Nova wave is released every 8 sec for 16 sec (so 2 extra waves)

Intermission 2 (25%) (lasts 1 minute)

During this intermission, the boss will begin channeling a new rune to augment his abilities.  He will be immune during this time.  He will also summon 1 Gorian Reaver, 2 Gorian Warmages, and Volatile Anomalies will spawn from the rune stone every 12 sec.

Gorian Reaver - Casts frontal/conal Devestating Shockwave, dealing massive dmg to all players in front of him.  Also applies a stacking tank debuff Crush Armor, increasing phys dmg taken by 25% for 25 sec.  Will also Kick to the Face (not joking), dealing massive dmg to the target, clears all threat and knocks the player back.

Gorian Warmages and Volatile Anomalies are the same as the first Intermission.

Phase 4 (25% to 0%) - Rune of Replication phase, primary abilities lose "Fortification" but are now augmented with "Replication" effects.

1. Arcane Wrath: Replication - Normal effects, however a 2nd player will be affected the FIRST time this jumps, so there will be 2 "wraths" out for the duration.
2. Destructive Resonance: Replication - Normal effects, however when the mine either explodes on its own or is triggered, 2 additional mines will spawn nearby. Unknown if this only occurs once or if this serves as a soft enrage (ie, getting overwhelmed with mines)
3. Replicating Arcane Aberration - Normal effects, once the add dies, will spawn into 7 "Remnant" adds.
4. Mark of Chaos: Replication - Normal effects, when this expires, 8 Orbs of Chaos spawn around the target(tank), these will fly outward from the player and deal massive arcane dmg to anyone they hit.
5. Force Nova: Replication - Normal effects, but anyone hit by this will also deal mild/moderate dmg to players within 4 yards of one another.

Summary

Fuck this fight... no seriously, FUCK this fight.... But I'll do my best.

Phase 1 - Let the Arcane Wrath jump a few times and have the 4th affected player run from group to lose the debuff.  As for the "Mine" from Resonance, you can either trigger it, or let it run its course.  Unsure what the preferred method is currently.  Nuke the Aberration add(s) that spawn.  Try to get through the Force Nova wave as fast as you can to negate as much of the dmg as you can.  Tanks run the Mark of Chaos debuff away from raid, and swap when appropriate due to Accelerated Assault stacks.

Phase 2 - Raid will have to move from the player affected by Wrath after its jumped so many times in order to get it to drop.  Probably once 1 person is affected, have it jump between 2 (maybe 3) designated people while the rest of the raid moves away to get it to drop.  The Resonance mine might need to be triggered due to the activation radius growing in size.  Again kill the Aberration add(s), but be wary of the knockback so you dont get thrown into a mine, etc.  For the Nova wave, if you are going to blink/leap through the wave, be sure you do it with accuracy so you dont land at the back edge of the effect and get stuck in it from the pushback for the entire duration.  Tanks be wary of being teleported near the raid with the Mark of Chaos debuff and still tank swap when appropriate.

Intermission 1 - Cleanse slowed players, and try to keep the Warmages separated (remember they fixate randomly).  Stay spread for their Nether Blast attack.  Kill the Volatile Anomalies, but try to stagger them a bit so you dont take raid-wide AoE from all 3 dying at once.  Perhaps use raid def/healing CDs when they die.

Phase 3 - Either deal with the Wrath longer, or get some designated people onthe other side of the room to make it jump a few times, then range it from farther away.  Resonance mines last twice as long, so you might have to detonate them to get rid of them. from taking up space in the room.  Focus the Aberrations as they have more health and you can't cc them.  Melee and Ranged will have to run away from the tank(s) when they get affected with Mark of Chaos.  May have to use some healing/def CDs on the last wave or 2 since there will be multiple waves that spawn instead of just the one.

Intermission 2 - Tanks tank the new Reaver add, tank swap and face it away from the raid (duh).  Might need to tank against/near a wall for the Kick to the Face.  Otherwise deal with the Warmages and Anomalies the same.

Phase 4 - Probably need to split the raid up in 1/2 to deal with the duplicate Wrath.  For the replicated Resonance mines, I would probably recommend letting them set.  They last a minute and you dont want to spawn multiples too early.  Probably nuke the Aberration and cleave down the Remnant adds that spawn... unless they deal massive dmg, in which case you may want to chain CC the Aberration(s).  Tanks run away from raid (like normal) but raid needs to be wary of the Orbs of Chaos that will spawn/fly out from the tank when the debuff falls off.  For the Nova wave, try to stay spread 4 yards from others when dealing with the wave so you don't splash damage on everyone.

Mythic Differences

In Mythic, the fight changes to a 3-phase fight, still with 2 intermission phases.

Phase 1 (100% to 66%) - The fight STARTS with the bosses abilities augmented by BOTH "Displacement" AND "Replication" effects... YAY 2 TIMES THE FUCKING FUN!!!....

Intermission 1 (1 minute duration) - The only change is each time one of the Warmages successfully casts their Nether Blast it increases all damage done by 25% for 6 secs (stacks).

Phase 2 (66% to 33%) - The "Replication" effect fades, and the boss will now use both "Displacement" AND "Fortification" effects.... 'YAY' to 2 times the fucking fun AGAIN!!...

Intermission 2 (1 minute duration) - Same change as Intermission 1.  Nothing new in regards to the Reaver add.

Phase 3 (33% to 0%) - The "Displacement" effect fades, and the boss will now use both "Fortification" AND "Replication" effects.  You know the drill...  I'm just going to go cry in a corner now.

The following vid is NORMAL difficulty