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Caustic Grebuloff Boss (The Dead Ends)

Matt Chard

On this page you can find all the details needed to defeat Caustic Grebuloff, the first boss in the Level 90 Dungeon, The Dead Ends in Final Fantasy XIV Endwalker (FFXIV). Details on the mechanics along with how to tank and heal.

Caustic Grebuloff is the first boss of The Dead Ends.



This attack will always follow after the text appears telling you what way the wind will blow. It’ll then cast Miasmata which’ll cover the arena in a pool of Miasma that’ll add AoE circles around the arena that move in the direction that the wind is blowing. If you’re hit by one of the AoEs, you’ll get the Necrosis debuff that will instantly kill you if it isn’t cleansed immediately.

Sometimes Grebuloff will cast Wave of Nausea at the same time. When it does, find the small safe spot near the boss, then move the direction the wind is blowing like normal.

Cough Up

Grebuloff will drop three sets of AoEs under you, then finishes the mechanic with a marker above some party members heads. Avoid the AoEs, and after the last set, stack with the other marked players. If you don’t stack up, you’ll get a Hysteria debuff which makes you run towards the outside of the arena. If it follows this up with Wave of Nausea, you’ll get hit by that mechanic too.

(1 of 3) Cough Up will first place three sets of AoE circles under the party

Wave of Nausea

A huge donut-shaped AoE with the only safe areas being right by the boss or on the outer edges of the arena depending on where the boss is when he does this attack. If you’re near enough, run into the boss, but if you’re a ranged DPS, you may want to head to the edge of the arena.

(1 of 2) Wave of Nausea is a large donut AoE. Its safe spots are where the boss is or the edge of the arena.

Wave of Nausea is a large donut AoE. Its safe spots are where the boss is or the edge of the arena. (left), Pox Flail is Grebuloff's tankbuster. (right)

Pox Flail

This is your typical tankbuster. As always, use a defensive cooldown if you’re the tank, and be ready to heal the tank if you’re a healer.

Blighted Water

A simple party stack mechanic, the boss will drop an orange arrow marker on a random party member. Group up to share the damage.

(1 of 2) Blighted Water is a simple party stack attack

Blighted Water is a simple party stack attack (left), whilst Befoulment is a simple party spread attack. (right)


Grebuloff will place a purple targeted spread marker on all party members. Move away from each other to avoid overlapping the AoEs.


Caustic Grebuloff is a tricky first boss of a dungeon, mainly thanks to its Miasmata mechanic. When you see the text “A northward wind begins to blow…”, you’ll see wind on the arena traveling to the north, then Grebuloff will cast Miasmata which places AoE circles all over the arena.

When the cast finishes, the AoE circles will start going on and off in the direction that the wind is blowing. You’ll want to find a safe spot from the AoEs and slowly move the wind direction to avoid them because if you’re hit by one, you’ll get a Necrosic debuff (similar to Doom) that’ll instantly kill you in a couple of seconds. This can be erased, so healers may want to keep an eye on the party’s debuff icon to see if anyone got hit by it.

Sometimes, Grebuloff will cast Wave of Nausea at the same time, which is a huge donut AoE around itself. This will leave a small safe spot in front of it. If it casts Wave of Nausea on its own, you can either run into the boss or the edge of the arena to avoid the attack.

The only other mechanic that may cause some confusion is Cough Up. This’ll place three sets of AoEs under everyone’s feets so keep moving to avoid getting hit by them. After the AoEs have stopped, some players will get a small orange/red marker above their head that indicates you have the Craven Companionship debuff that requires you to stack up otherwise the debuff will stay on you and go off giving you Hysteria (Fear) in the next mechanic.

Other than that, you’ll have to face a few more basic mechanics like Befoulment (Spread markers), Blighted Water (Stack marker), and Pox Flail, which is a tankbuster.

How to Tank

How to Heal


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Guide Information

  • Publisher
    Square Enix
  • Platforms,
    Mac, PC, PS4, PS5
  • Genre
  • Guide Release
    3 December 2021
  • Last Updated
    12 January 2023
    Version History
  • Guide Author

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Welcome to our Final Fantasy XIV: Endwalker guide! Endwalker is the fourth expansion for Final Fantasy XIV after the last expansion Shadowbringers. This guide currently contains the following:

NEW - Updated for patch Patch 6.2

Patch 6.0

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