Heroic WoTLK Raid Achievement Guide
Heroic: Besting the Black Dragonflight: Defeat Sartharion the Onyx Guardian on Heroic Difficulty. In other words do 25man Obsidian Sanctum.
Heroic: Less Is More: Defeat Sartharion the Onyx Guardian and the Twilight Drakes with fewer than 20 on Heroic Difficulty. Requires you to have 20 or less people in the raid when you kill Sartharion. Find 20 good people and go to town.
Heroic: The Arachid Quarter: Defeat all of the bosses of the Arachnid Quarter in Naxxramas. You'll be required to kill Anub'Rekhan, Grand Widow Faerlina and Maexxna in 25man Naxx.
Heroic: The Construct Quarter: Defeat all of the bosses of the Construct Quarter in Naxxramas. You'll be required to kill Patchwerk, Grobbulus, Gluth and Thaddius in 25man Naxx.
Heroic: The Plague Quarter: Defeat all of the bosses of the Plague Quarter in Naxxramas. You'll be required to kill Noth the Plaguebringer, Heigan the Unclean and Loatheb in 25man Naxx.
Heroic: The Military Quarter: Defeat all of the bosses of the Military Quarter of Naxxramas. You'll be required to kill Instructor Razuvious, Gothik the Harvester and The Four Horsemen in 25man Naxx.
Heroic: Sapphiron's Demise: Defeat Sapphiron on Heroic Difficulty in Naxxramas. Sapphiron is one of the final bosses of Naxxramas.
Heroic: Kel'Thuzad's Defeat: Defeat Kel'Thuzad on Heroic Difficulty in Naxxramas. Kel'Thuzad is the final boss of Naxxramas.
Heroic: The Fall of Naxxramas: Defeat every boss in Naxxramas on Heroic Difficulty.
Heroic: The Dedicated Few: Defeat all of the bosses in Naxxramas with 20 or less people. The key to this achievement is find 20 good people and go to town.
Heroic: Arachnophobia: Defeat Maexxna in Naxxramas within 20 minutes of Anub'Rekhan's death on Normal Difficulty. Don't take long with loot and don't wipe.
Heroic: Make Quick Werk Of Him: Defeat Patchwerk in Naxxramas on Heroic Difficulty in 3 minutes or less. This requires your raid to have an average of 70,000 DPS.
Heroic: The Safety Dance: Defeat Heigan the Unclean in Naxxramas on Heroic Difficulty without anyone in the raid dying. This is a rather easy achievement to do, just don't bring any retards.
Heroic: Momma Said Knock You Out: Defeat Grand Widow Faerlina in Naxxramas on Heroic Difficulty without dispelling or preventing frenzy. Have a really good geared tank hop on Faerlina and another tank on the adds. From there just mass DPS Faerlina.
Heroic: Shocking: Defeat Thaddius in Naxxramas on Heroic Difficulty without anyone in the raid crossing the negative and positive charges. For tips on how to do this achievement click here. The easiest method to do this is by splitting everyone up into two groups, a positive and a negative group. These two groups will need to move clockwise for positive and negative charges. Generally you'll have someone knowledgeable in your raid if you're trying for this achievement. Just listen to them and don't suck.
Heroic: Subtraction: Defeat Thaddius in 25 man Naxx with 20 or less people. Find people who don't suck and want this achievement too and go to town.
Heroic: Spore Loser: Defeat Loatheb in Naxxramas on Heroic Difficulty without killing any spores. Completely ignore the spores and make sure you don't have retribution aura up, thorns or any other buffs that will damage something that attacks you. Also your raid will need to have awesome DPS.
Heroic: And They Would All Go Down Together: Defeat all of the Four Horseman within 15 seconds of each other. This achievement is semi difficult. The hardest thing is not reaching the 20 minute enrage timer. Strategies for how people accomplished this achievement.
Heroic: The Hundred Club: Defeat Sapphiron on Heroic Difficulty in Naxxramas without any member of the raid having over 100 frost resistance.
Heroic: Just Can't Get Enough: Defeat Kel'Thuzad in 25man naxx while killing at least 18 abominations in his chamber. You will need to pull some extra abom's from around the room. They will spawn after you engage Kel'Thuzad.
The Immortal: Don't let anyone die on any boss encounter and you'll get this achievement. Plus the title "The Immortal" as well.
Heroic: The Spellweaver's Downfall: Defeat Malygos on Heroic Difficulty.
Heroic: You Don't Have An Eternity: Defeat Malygos in 6 minutes or less on Heroic Difficulty.
Guide on how to defeat Malygos in 6 minutes
Heroic: A Poke In The Eye: Defeat Malygos with 20 or less people.
Heroic: Denyin' the Scion: Deliver a killing blow to a Scion of Eternity while riding on a hover disk on Heroic Difficulty. When you kill a Arcane Lord or Arcane Scion during the Malygos encounter they drop a Hover Disk for you to ride. Once you're on this disk, get a killing blow on one of the Scions.
Heroic: Gonna Go When the Volcano Blows: Defeat Sartharion the Onyx Guardian on Heroic Difficulty without getting hit by Lava Strike. This achievement only requires YOU to avoid Lava Strike, if someone else in the raid gets hit by it, they will not get the achievement but you still will.
Note: Since the Lava Strike is completely random some groups will let people die early on in the fight to allow them to get this achievement. You can easily die from Sartharion by getting Breathed or being hit by the Lava Wall.
Heroic: Twilight Assist: With at least one Twilight Drake still alive, engage and defeat Sartharion the Onyx Guardian on Heroic Difficulty. The easiest drake to do this with is Tenebron.
Obsidian Sanctum Instance Guide
Heroic: Twilight Duo: With at least two Twilight Drakes still alive, engage and defeat Sartharion the Onyx Guardian on Heroic Difficulty. The two easiest drakes to do this with are Tenebron and Shadron. You'll need a semi knowledgeable group to do this.
Obsidian Sanctum Instance Guide
Heroic: The Twilight Zone: With at least three Twilight Drakes still alive, engage and defeat Sartharion the Onyx Guardian on Heroic Difficulty. This is the hardest one to do.
Obsidian Sanctum Instance Guide
Onyxia's Lair (25 Player): Defeat Onyxia in Onyxia's Lair on 10 player mode. Onyxia's Lair is located in Dustwallow Marsh, just south of Mudsproket, the goblin town. In order to defeat Onyxia you will need 2 tanks and usually a Ranged DPS heavy group.
More Dots! (25 Player): Defeat Onyxia in less than 5 minutes. This will require a coordinated group as well as a ranged DPS heavy group to get her out of Phase 2 asap. It is also advised that you bring a Shaman for Bloodlust.
Many Whelps! Handle It! (25 Player): Cause 50 Onyxia Whelplings to Hatch within 10 seconds of Onyxia's Liftoff. This means you will need to have someone agro another 50 Whelps at the very start of Phase 2. A rogue popping evasion and sprint to agro the whelps is generally the safest way. How ever you work it, just make sure your tank is ready to pick up the extra 50 whelps.
She Deep Breaths More (25 Player): Defeat Onyxia without anyone taking damage from Deep Breath. Deep Breath is an ability that Onyxia uses during phase 2. The way to avoid it is have everyone get to the walls, out of the middle of the area. If everyone does this, then they will not be hit by it. In other words, if you have no retards you'll get this achievement.