Heroic Kel'Thuzad Boss Guide

Written and produced by Crzypck

Special thanks to our consultant: Tagzz

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Kel’Thuzad

KT is a three Stage encounter. You’ll alternate between Stage 1 and Stage 2 three separate times. Once you’ve completed Stage 2 for your third and final time, you’ll transition into Stage 3. Being that this is the penultimate boss of the raid, there’s a whole hell of a lot going on, including two separate planes of existence for Stage 2.

Stage 1 Abilities

  • Kel’Thuzad has a mana bar. Several abilities cost Mana
    • He only uses Mana in Stages 1 and 3
    • Abilities using mana include Oblivion’s Echo, Glacial Wrath, and Frost Blast
    • In Stage 1, abilities cost 20% mana. In Stage 3, they cost 40%
  • Howling Blizzard
    • When KT reaches 0% Mana, he casts Howling Blizzard for 20 seconds that’ll leave ice patches on the ground
    • Standing in ice patches deals 13k Frost damage per second
    • These patches grow over the 20 second cast, then explode, dealing 50k Frost to anyone inside a puddle.
      • This is similar to how Wrathion’s fire patches worked. Start small, grow over time, then explode
      • They’ll cover a large portion of the room, so you’ll need to find a safe spot
    • When this cast finishes, the boss’s Mana is reset to 100%
  • Soul Fracture
    • Tank smack, deals mild Shadow damage & knocks the tank back
    • Also creates 3 Soul Shards of the tank
      • These are adds that spawn around the room, and must be killed
      • Each add applies a stack of Soul Exhaustion to the tank who was hit with Soul Fracture
        • Each stack increases Physical damage taken by 500%
        • Lasts 1 minute
      • Killing a Soul Shard removes a stack of the tank’s debuff
      • In addition to all this, the adds periodically cast Piercing Wail, dealing 12k Shadow damage to the raid
    • If all 3 Soul Shards are not killed within 1 minute, the affected tank dies.
  • Oblivion’s Echo
    • Puts a green circle debuff on several players for 6 seconds
    • Being inside the circle silences and pacifies you, 10 yard range
    • When this expires, it’ll leave the same circle just on the ground for 6 seconds
      • After 6 more seconds, the ground circle expires, and a Frostbound Devoted add spawns
        • These adds fixate a random target, and explode for 33k Shadow damage to anyone within 5 yards if they reach their target
  • Dark Evocation
    • Kel’Thuzad revives all slain Frostbound Devoted and makes them fixate again, and all slain players are resurrected and Mind Controlled to fight for KT
      • Kill your friends. You didn’t need them anyways, damn leeches.
  • Glacial Wrath
    • Puts a blue arrow above several players’ heads
    • After a few seconds, puts a swirlie down next to the targeted players. The swirlie then explodes, dealing 29k Frost damage to anyone hit & knocking them back
    • Leaves behind a Glacial Spike
      • These have a health bar, and lose 5% HP every 2 seconds
      • When they die, they explode and cast Frozen Destruction
        • Deals 16k Frost to all players, and applies a DoT to the raid
        • DoT deals 2k Frost per second for 10 seconds. Stacks. New stacks refresh duration
  • Frost Blast
    • Puts a giant soak circle on a random player, explodes after a few seconds
    • Deals 165k Frost damage, divided evenly by everyone hit
      • Also gives everyone hit a DoT, deals 5k Frost per second for 12 seconds
      • Also puts Frozen Binds on everyone hit, rooting them for 12 seconds
        • Dispellable, breaks from basically any anti-root ability.
  • Ice Shard
    • Tank smack, deals a big chunk of Physical damage
  • When Kel’Thuzad’s HP reaches 0%, you transition into Stage 2.

Stage 2 Abilities

  • In Stage 2, there’s two distinct planes of existence - the main platform and the Phylactery
    • In the KT plane, you’ll be fighting some undead-type adds
    • In the Phylactery plane, you’ll be killing the Remnant of Kel’Thuzad
    • The phase ends either when Vengeful Destruction & Undying Wrath go off, OR when the Remnant has lost 40% of his HP (or died)
    • Remnant’s HP persists through the encounter. The first Stage 2 ends when it reaches 60% HP remaining, second Stage 2 ends at 20% HP remaining, third Stage 2 ends when the Remnant dies.
  • At the beginning of Stage 2, KT becomes untargetable and starts casting Vengeful Destruction
    • Lasts 45 seconds
    • If this cast goes off, deals 50k Shadow to the raid
    • Interrupted when the Remnant has lost 40% of its HP (or dies)
  • Also at the beginning of the phase, KT turns green. Running and standing directly under KT ports you into the Phylactery plane
  • Kel’Thuzad’s Plane
    • KT summons some undead mods
    • Unstoppable Abomination
      • Abomination add, smacks your tank for big chunks of Physical damage
      • Also casts Demonish, shooting a wave of necrotic energy in a straight line towards a random player, dealing 31k Shadow to anyone hit
    • Soul Reaver
      • Banshee add. Periodically casts Banshee’s Cry
        • Launches a missile at random players every second, dealing 6k Shadow to the targets
        • Each set of missiles has their damage increased by 25%
        • Interruptible
    • Undying
      • Any adds killed in the Kel’Thuzad plane while the Phylactery is still open (meaning before the Remnant has lost 40% HP or dies), respawn after being dead 10 seconds and continue fighting you
  • Phylactery
    • Remnant of Kel’Thuzad stands there and lets you wail on him, but casts several things at the platform
    • Sinister Miasma
      • Deals 400 Shadow damage every 2 seconds while in the Phylactery
      • Stacks, meaning the damage down here ramps up dramatically over time
    • Shadow Fissure
      • Blue swirlies constantly appearing on the ground, exploding after a few seconds and dealing 31k Shadow to anyone hit by the explosion
      • Just move out of swirlies
    • Freezing Blast
      • Frontal ice thing, exactly like what Jaina did
      • Casted at a random player in the Remnant’s plane
      • Deals 10k Frost to anyone hit, and roots them
    • Glacial Winds
      • This ability is only present in your 3rd and final Stage 2
      • Creates several tornados that radiate out from the caster, spinning around the room from the center, eventually to the edge
      • Deal 1k Frost to anyone who touches them, and roots you for 4 seconds
    • Undying Wrath
      • When the Remnant reaches either 60% or 20% HP, he starts casting Undying Wrath
      • This is a 10s cast, and basically kills anyone who stays in the Phylactery plane
      • This is when you run to the portal and leave
  • Soul Marked
    • If you enter the Phylactery, then leave it, you’re unable to re-enter during that specific occurrence of Stage 2.
    • This does NOT prevent you from going into each Stage 2 Phylactery.
    • You CAN have the exact same group go down each Stage 2
  • Lots of info in this section, so let’s sum it up
    • There’s 2 Planes here - KT and Remnant
    • KT plane = undead adds that respawn 10s after they die
    • Remnant plate = swirlies and frontal, plus tornados the 3rd time
    • You have 45s to push the Remnant 40% HP
      • When the Remnant casts Undying Wrath, if you’re in his plane, run to the portal and GTFO
  • You’ll repeat Stage 2 three separate times.
    • Necrotic Surge
      • Each time a Stage 2 ends, Kel’Thuzad revives with 100% HP and increases his damage by 5%
      • Also causes Oblivion’s Echo and Glacial Wrath to target more people for the remainder of the encounter
    • Necrotic Empowerment
      • Any adds that aren’t dead on the main platform when Stage 2 ends are buffed, increasing damage by 25% and becoming immune to crowd control
    • Once you’ve completed the third Stage 2 and the Remnant is killed, you’ll enter Stage 3

Stage 3 Abilities

  • Sinister Miasma
    • Same thing as in the Phylactery - 400 Shadow damage every 2 seconds, stacks, damage ramping up over time
  • Deep Freeze
    • Creates ice patches periodically that last for the remainder of the encounter
    • Standing in ice deals 13k Frost damage per second
  • Onslaught of the Damned
    • Kel’Thuzad calls more of the Stage 2 adds throughout all of Stage 3, which must be tanked and killed
    • Additionally, whenever this is cast, any dead players are resurrected & mind controlled to fight for Kel’Thuzad
  • Frost Blast & Ice Shard
    • Same as in Stage 1

Strategy

Stage 1

  • Tank Kel’Thuzad a bit off-center
  • When Soul Fracture goes out, tank swap on boss
    • The raid should kill off the Soul Shards as quickly as possible, so you don’t miss the 1 minute timer and have your tank just die, and to minimize how many casts of Piercing Wail go off
  • Players affected by the Oblivion’s Echo debuff should move towards the edges of the room to drop their circles
    • When the Frostbound Devoted adds spawn, throw some slows up on them and DoT them up
    • These aren’t #1 priority, but you don’t want to completely ignore them
    • If you’re fixated by one of the adds, just kite it. Don’t let it reach out
  • Players affected by Glacial Wrath should make sure they’re not standing on top of each other
    • When the Glacial Spikes pop out, you’ll need to stagger killing them because of the DoT stacking
    • Your Raid Leader should mark a Skull, and all DPS should hardswap to this and blow it up
    • When the DoT has 2 seconds left, the Raid Leader should call the next Spike to kill, and DPS should swap
    • Continue this for the remaining Spikes
    • When the RL calls for killing a Spike, that becomes absolute #1 kill priority above all else
    • Whichever Spikes aren’t actively being focused, should largely be ignored. Don’t DoT or pad on the rest of them - it could actually cause a wipe if you accidentally kill a Spike too early and the raid’s debuffs refresh
  • For Frost Blast, you’ll want 5 or 6 people helping soak to split the damage. More than 8 soakers could be an issue due to the DoT effect everyone gets.
    • Use whatever you can to break the roots. Dispels, Mass Dispel, Blessing of Freedom, whatever you have
    • If possible, use a damage mitigation CD like AMZ or Barrier to help with the initial damage of the explosion
  • When the Howling Blizzard is cast, find a safe zone
    • There will be several safe zones of varying sizes. Any works, just make sure you don’t stand in a puddle
  • After Kel’Thuzad casts Dark Evocation, make sure to slow the adds that respawn and throw DoTs on them. If there’s no Spikes or Soul Shards out, blow up the Devoted dudes
  • For the second and third occurrences of Stage 1, keep in mind the buffs KT gets
    • The second Stage 1, he’ll do 5% more damage. The third, he’ll be doing 10% more damage
    • Additionally, there’ll be more people getting Oblivion’s Echo and Glacial Wrath each time
      • This means more Frostbound Devoted adds each time, and more Glacial Spikes
      • The Spikes in particular get to be an issue
        • By the 3rd Stage 1, you’ll likely need to kill 2 Spikes at the same time early on, using at least 1, if not 2, healing CDs to keep the raid stable. Without doing this, you simply might not have enough time and risk an accidental refresh instead of an intentional one

Stage 2 Strategy

  • Since there’s 2 distinct planes you fight on, we’ll discuss each separately
  • You should send down about ⅓ of your DPS for each Stage 2
    • You’ll want to send down your bursty single-target DPS for this. You can send down the same group each time, so having good ST burst helps speed this phase up
    • Tanks do not need to go into the Phylactery
  • Kel’Thuzad’s plane
    • Tanks need to pick up the adds, make sure they aren’t just smashing your raid
    • Interrupt the Soul Reaver casts as much as possible
    • In an ideal world, coordinate killing the adds when the Phylactery folks, so the adds die within 10 seconds of the Remnant reaching his health breakpoint
    • By doing this, you’ll avoid respawns of the adds completely
  • Phylactery plane
    • Dodge swirlies, they come pretty much non-stop
    • Don’t get hit by the frontal. It’s super obvious, literally the same spell that Jaina did
    • In the third Stage 2, avoid the tornados. They start at the boss, spinning outwards. Probably wait a few seconds before going in, or they’ll just blast through you
    • Coordinate your push timing if possible, as stated above

Stage 3

  • You’ll want to pop lust as soon as Stage 3 begins
  • This is a wild, chaotic race
    • Sinister Miasma means there’s ticking damage the whole Stage, increasing in power the longer the boss lives
  • Deep Freeze will slowly fill up the encounter room, forcing you to move to avoid the puddles and have space to work with
  • Adds continue spawning, meaning you have to deal with them. Tank them on the boss for cleave/AoE, but focus damage should be on Kel’Thuzad himself
  • Keep soaking Frost Blast as you were in Stage 1
    • As you get into the later stages here, it may be worthwhile to just sacrifice the target of Frost Blast
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