Defeat Trollgore on Heroic difficulty before Consume reaches ten stacks.
Trollgore casts Consume every 15 seconds. That's 15 seconds for the tank to position Trollgore in a niche or hallway that gives time for the DPS and healer to run out of Trollgore's line-of-sight.
Position an off-tank or melee DPS at the top of the stairs to deal with the adds that show up while the rest of the team takes to the fight downstairs.
Tank him in the hallway that you used to enter the room, with the DPS and healer standing behind either column. Every 10 seconds, everyone but the tank should hide before Trollgore casts consume.
Defeat Novos the Summoner on Heroic difficulty without allowing any undead minions to reach the floor.
The group only needs to position themselves on the stairs with the healer positioned to heal the off-tank and main tank. The minions themselves deal pitiful damage and don't swarm that well, so dealing with them until Novos' shields go down shouldn't be a problem.
Better Off Dred
Engage King Dred on Heroic difficulty and slay 6 Drakkari Gutrippers or Drakkari Scytheclaws during his defeat.
The raptors needed for this fight are located in King Dred's pen. Save time by waiting for King Dred to approach the entrance before you pull him, pulling 1 or 2 raptors at the same time.
Kill the raptors and as the fight progresses, pull more raptors to your tank by any means. The Gutrippers can reduce their target's stamina by 15% only once. Don't go overboard with pulling the Scytheclaws because each Scytheclaw can put a bleed effect on their target. Couple the bleed damage with Dred's damage and his bleed damage amplification skills and only a miracle will save your tank.
These raptors do not respawn. If you kill too many, try this achievement again tomorrow.
Defeat Cyanigosa on Heroic difficulty without using Defense Control Crystals and with Prison Seal Integrity at 100%.
This is no real achievement. Many players don't notice the pink crystals on the walls around the room and can still keep the entry door at 100% the entire time. Wiping doesn't affect this achievement either.
Defeat Xevozz, Lavanthor, Ichoron, Zuramat the Obliterator, Erekem and Moragg on Heroic difficulty.
Run the dungeon a few times and if you're not so lucky, spend the next week or so trying to unlock that one last boss for this achievement.
Defeat Ichoron on Heroic difficulty without allowing any Ichor Globules to merge.
Don't expect to do this at the same time as Defenseless.
As you fight Ichoron, her shield loses a stack for every hit she takes. Once those stacks are gone, she explodes into several Ichor Globules that spread around the room and merge in the center.
Around the room are several pink crystals along the walls. Assign someone to click on them whenever Ichoron's shield reaches 7-10 stacks. The crystals have a charge-up time. By the time the globules are out, the defense crystal should be ready to fire. After it fires, find another crystal for the next split.
A Void Dance
Defeat Zuramat the Obliterator on Heroic difficulty without killing any void sentries.
Focus fire on Zuramat the Obliterator, but have your dispels ready. His Shroud of Darkness reduces healing done to his attackers by 20% for each stack to a maximum of five stacks. With the AoE shadow damage done by the Void Sentries, this can turn very ugly if you spend more than a minute fighting him.
What the Eck?
Defeat Gal'darah on Heroic difficulty while under the effects of Eck Residue.
After killing everything in Gundrak except for Eck the Ferocious and Gal'darah, pay a visit to the giant gorloc. He's in the tunnel that opens up after defeating Moorabi.
While fighting Eck, stand in front of him when he casts Eck Spit. It stings, but it's the only way to get Eck Residue. Enjoy your ferocious smell for an hour.
Now make your way to Gal'darah and don't die until he does. You'll lose your Eck Residue if you do. Any immunity spells such as Ice Block and Divine Shield, so keep your fingers off your panic buttons.
Defeat Moorabi on Heroic difficulty while preventing him from transforming into a mammoth at any point during the encounter.
This achievement is a pain in the arse. The more damage you deal to Moorabi, the faster his transformations are. And if he transforms towards the end of his miserable life, your DoTs might kill him.
There are several party setups that will work. Some of the more popular ones involve at least one shaman with Reverberation who uses Wind Shear whenever it's available.
His base cast times are 10 seconds while he's above 50% HP, then 5 seconds below that. The cast speed increases based on how much health he has left. Below 30%, that cast time could be instant.
Depending on your latency, you can either time your interrupts or use one every 2-3 seconds after he reaches 30%.
Share The Love
Defeat Gal'darah on Heroic difficulty and have 5 unique party members get impaled throughout the fight.
While Gal'darah's a rhino, he'll impale one party member for a few seconds, dealing bleed damage while parading them around. If you're lucky, he'll impale each party member only once. If he feels like making you suffer for this achievement, you'll get repeated impalements for one party member. If Blizzard feels like making you suffer, your heal will disconnect and you'll wipe and have to do this all over again.