Hydross the Unstable Guide: Strategy, Abilities, Loot

Last updated on Aug 31, 2021 at 00:44 by Sellin 1 comment

Hydross the Unstable is the first boss in the Serpentshrine Cavern 25-player raid instance. Hydross is a unique challenge that will require your tanks to acquire special sets of gear to handle his massive elemental damage, while also stressing the importance of boss positioning.



Hydross the Unstable is the first boss in the Serpentshrine Cavern raid instance. Hydross is an Elemental that has two major phases consisting of a Frost phase and a Nature phase; the boss will shift back and forth between the two depending on his positioning. This is a two-tank boss that will require one tank to have a Nature Resistance set ready and the other tank to have a Frost Resistance set.


Role-Specific Tips for Hydross the Unstable


Healer Tips

The raid will need to be spread during the Frost phase so assigning locations to your healers prior to fighting the boss will help stop range-related deaths.

When the boss transitions four adds will spawn. The time that the adds are alive is likely to be the highest tank damage so coordinate with your tanks and other healers on cooldown usage during the transitions.

Tank healing is the most important part of this fight as damage to the raid is generally quite low if the Water Tomb IconWater Tombs are handled correctly.


Tank Tips

Understanding where you have to move Hydross to change the phase is extremely important. Causing phase changes spawn very dangerous adds that, if you are not prepared for them, can lead to quick deaths for non-tanks and possibly even wipe the group.

Frost and Nature resistance greatly mitigate the damage that Hydross deals. Each tank should be using a different resistance set and coordinating taunts with phase changes is crucial.

Threat resets when the phase change happens so it is important to save high-threat generators for these transitions because the boss is immune to taunt.


DPS Tips

All damage must stop when a transition is about to happen as threat is completely wiped when Hydross transitions to a new element. Hunters can take advantage of Misdirection IconMisdirection but make sure you are Misdirecting the correct tank as the person who is tanking changes every transition.

The Elemental adds are the biggest priority and should be focused down before hitting the boss. This limits the amount of damage going out and allows for your tanks to establish a threat lead on Hydross so you can DPS.

Make sure you are spread to avoid dealing unnecessary damage with Water Tomb IconWater Tomb.


Hydross the Unstable Abilities

  • Mark of Hydross IconMark of Hydross — Mark of Hydross is a stacking debuff that affects every member of the raid. Every 15 seconds the potency of this debuff increases, scaling from 10%, to 25%, to 50%, to 100%, to 250%, and maxing out at 500% Frost damage taken.
  • Mark of Corruption IconMark of Corruption — Mark of Corruption is a stacking debuff that affects every member of the raid. Every 15 seconds the potency of this debuff increases, scaling from 10%, to 25%, to 50%, to 100%, to 250%, and maxing out at 500% Nature damage taken.
  • Water Tomb IconWater Tomb — This is a high-damage targeted ability that will randomly select a player before stunning all players within 8 yards of the target and dealing Frost damage over the duration of the debuff. Hydross will only cast this during the Frost phase.
  • Vile Sludge IconVile Sludge — This will randomly be cast on a member of the raid dealing damage-over-time and reducing the damage they deal and the healing they will be able to receive by 50%. Hydross will only cast this during the Nature phase.
  • Summon Water Elemental IconSummon Water Elemental — Hydross will spawn four Elementals when transitioned. The adds that will spawn depend on what phase Hydross is entering; Pure Spawn of Hydross is the Frost version and Tainted Spawn of Hydross is the Nature.

Strategy for Hydross the Unstable


Pulling the Boss

Two tanks are required for Hydross, one with a Nature Resistance set and one with a Frost Resistance set. Hydross will begin the fight in his Frost phase so the tank who has the Frost Resistance should be the one to begin the fight.


Frost Phase

During the Frost Phase Hydross only has two abilities: Water Tomb IconWater Tomb and Mark of Hydross IconMark of Hydross. Water Tomb can be dealt with by all members of the raid spreading out and not being within 8 yards of another raid member. Healers will need to be ready to heal the person who is Water Tombed as they can take a large amount of damage depending on how many Mark of Hydross stacks are active. Mark of Hydross is a stacking raid debuff that is dispelled by transitioning the boss between phases. This debuff stacks every 15 seconds and after the fourth application of this debuff, when it is dealing 100% bonus Frost damage to the raid, you should look to transition the boss as the damage can quickly become unhealable.


Transitioning Hydross

Hydross' starting position is between two large pillars where you will see beams being casted into the boss from them. Detaching Hydross from these beams by moving him off of his starting platform past the two flags planted in front of the boss will cause him to transition to his Nature phase. Returning him to his original positioning will transition him into his Frost phase. Every time the boss transitions he will spawn four Elemental adds that must be tanked and killed as quickly as possible, so keep this in mind when deciding how often your group wants to transition the phases. Hydross' threat is reset every time a transition occurs so it is important to stop damage on the boss when you are preparing to transition.


Nature Phase

During the Nature Phase Hydross still only has two abilities: Vile Sludge IconVile Sludge and Mark of Corruption IconMark of Corruption. Vile Sludge is considerably less lethal than Water Tomb IconWater Tomb and does not require spreading, but it deals damage over time to its target while also reducing their damage dealt and healing received by 50% so it is important to still keep an eye on those affected by it, especially with more stacks of Mark of Corruption. Mark of Corruption acts the same as Mark of Hydross and can be handled identically to it. Transitioning back to Frost when the Mark of Corruption is at 100% bonus damage is the safest way to handle the mechanic.


Hydross the Unstable Loot

Item Item Type Slot
Living Root of the Wildheart Icon Living Root of the Wildheart Accessory Trinket
Idol of the Crescent Goddess Icon Idol of the Crescent Goddess Accessory Relic
Scarab of Displacement Icon Scarab of Displacement Accessory Trinket
Fathomstone Icon Fathomstone Accessory Off Hand
Band of Vile Aggression Icon Band of Vile Aggression Accessory Ring
Ring of Lethality Icon Ring of Lethality Accessory Ring
Brighthelm of Justice Icon Brighthelm of Justice Plate Helmet
Pauldrons of the Wardancer Icon Pauldrons of the Wardancer Plate Shoulders
Blackfathom Warbands Icon Blackfathom Warbands Mail Bracers
Ranger-General's Chestguard Icon Ranger-General's Chestguard Mail Chest
Shoulderpads of the Stranger Icon Shoulderpads of the Stranger Leather Shoulders
Boots of the Shifting Nightmare Icon Boots of the Shifting Nightmare Cloth Boots
Wraps of Purification Icon Wraps of Purification Cloth Bracers
Robe of Hateful Echoes Icon Robe of Hateful Echoes Cloth Chest


  • 31 Aug. 2021: Guide added.
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