The Ostrons believe the Hydrolyst is an omen of impending natural disaster. Stories describe a distinct, pungent aroma that precedes the arrival of this toxic beast.

The Eidolon Hydrolyst is a titanic spectral Sentient Eidolon creature that can be summoned on the Plains of Eidolon at night, acting as one of the Grand Bosses of the landscape. This is the third and final of the 3 night bosses of Plains of Eidolon, preceded by Eidolon Teralyst and Eidolon Gantulyst. This one is large enough to wield the landing strut of an ancient spacecraft as a weapon, and its arcane energies create localized storm systems wherever it surfaces.

All Eidolons are remnants of a Sentient that was defeated in a battle against the Tenno during the Old War, whose remains now wander the plains perpetually searching for their lost components. These fragments are, however, still formidable creatures armed with powerful attacks and near-impenetrable defenses, and are hostile to both Tenno and Grineer alike.

It is important to note players that have not unlocked Transference from The War Within won't have any means to properly fight the Eidolon Hydrolyst.


The shrine located in the middle of Gara Toht lake.

After Tenno capture the Eidolon Gantulyst, they must offer their Radiant Eidolon Shards on the Eidolon shrine located in the middle of Gara Toht Lake. This will cause the Eidolon Hydrolyst to emerge from the lake, marked by a column of green light.

The Hydrolyst generally walk in one direction, even if the Tenno are nearby, though their attention can be drawn to specific locations by using Eidolon Lures found throughout the Plains at night. The Hydrolyst has many different attacks which do extremely high damage, and while most of those attacks are telegraphed, they may remain quite hard to dodge, even with extensive use of the Operator's Void Mode. Like the preceding Gantulyst, the Hydrolyst is unusually mobile for its sheer size.

  • Enhanced Seeking Projectiles: A sphere of light emitted from the Hydrolyst's back which splits into multiple homing projectiles. These are more accurate than the Teralyst's, and are harder to avoid.
  • Ground Stomp: Stomps the ground, sending out a ground shockwave that knockbacks back any Tenno in its path a great distance (100 meter radius).
  • Ground Smash: Smashes the ground, sending out a series of high-damaging, homing quakes to the Tenno's position. These homing quakes can stun the Tenno and are 25m high. These quakes do not return to the Hydrolyst's position, and instead disappear at their stopping point and spawn green bubbles in the air that will slowly float up and grow in size, though they can be shot down using amps. Failing to shoot down these bubbles in time will cause them to detonate, dealing a considerable amount of magnetic damage with a guaranteed magnetic proc in a large area.
  • Gun Swing: Swings its gun arm while firing it in a wide arc, each bullet creating a 2m wide explosion.
  • Summoning Scream: The Hydrolyst glows green and screeches into the air. This will summon and buff Vomvalysts around it, also sending Red Orbs to nearby Vomvalysts, making them a Red Glowing variant armed with an Opticor-like beam that is fired in a cone shape that deals immense damage to Operators and Warframes alike after aiming.
  • Regenerating Scream: The Hydrolyst glows green and screeches. This will cause surrounding Vomvalysts (that are not affected by Summoning Scream) to link to the Hydrolyst and begin to regenerate its shields. Additionally, this will render it invulnerable to all damage until all linked Vomvalysts are destroyed. Red Glowing Vomvalysts are turned into a Blue Glowing variation which links to near Vomvalysts and has large amounts of Overshields.
  • Enhanced Sentient Residue: The Hydrolyst will "bleed" teal blood on the ground after losing at least one of its Synovia, dealing a lot of damage over time to those standing on it.
  • Enhanced Star Fall: Fires its gun into the sky, causing a rain of explosive, slightly homing projectiles on all targets nearby. The explosives may cause knockdown. Most of the projectiles spawn right under players. This ability can deal damage through LimboIcon272.png Limbo's Rift Plane and FrostIcon272.png Frost's SnowGlobe130xDark.png Snow Globe. Base area-of-effect spans a 300m radius.
  • Vomvalyst Bloom Summon: Throughout the fight, the Hydrolyst summons Vomvalyst Blooms, purple portals that will periodically spawn buffed variants of the Eidolon Vomvalysts. The blooms can also link to nearby Vomvalysts, making them immune to damage, and charging them up over time. Fully charged Vomvalysts gain a large amount of overshields and are visually indicated by a bright energy aura surrounding them. The Bloom can be destroyed, but takes massively reduced damage from anything other than Operator attacks and Amps.
  • Acid Rain: If at least one limb destroyed, the Hydrolyst will occasionally spawn clouds of acid rain, that cover a wide area, staining the ground green and dealing extreme damage to players standing on it.
  • EMP Bubbles: The Hydrolyst will periodically create bubbles of DmgMagneticSmall64.png Magnetic energy, increasing in frequency as more limbs are destroyed, that float into the air and grow until they explode into Energy Spike-like waves that are much faster and do extremely high damage, potentially one-shotting any player hit. However, these bubbles are telegraphed - they are preceded by streams of gas-like particles that emit from the ground, and the bubbles themselves take several seconds to grow large enough to explode. The bubbles can be destroyed before the explosion by gunfire, Operator attacks, and Amps.
  • Lightning (Passive): Throughout the fight, the Hydrolyst alters the weather around it, creating clouds of heavy rain and summoning highly damaging lightning. Small ripples of green energy on the floor briefly indicate where the lightning will strike. It seems the lightning cannot hit airborne players.
  • Energy Spike: The attack Hydrolyst will use upon the destruction of one of his limbs. This will emit five pulses of highly damaging DmgMagneticSmall64.png Magnetic damage.



Dealing with the Hydrolyst is essentially the same as dealing with its smaller counterpart the Gantulyst, in that it possesses 6 Synovia (one on each knee, one on each arm, and one on each of its shoulderblades), thus requiring the use of 3 charged lures if players wish to capture it.

Much like the Gantulyst, the Hydrolyst moves quickly, forcing the Tenno to run after it at all times and making it harder to hit its weak points.

The Hydrolyst remains immune to XakuIcon272.png Xaku's DmgVoidSmall64.png Void abilities.

As powerful as they are, the majority of the Hydrolyst's attacks only affect players on the ground. Spending time airborne is an efficient alternative to the Operator's Void Mode to dodge the attacks.


  • Preparation Phase: Damage an Eidolon Lure and hack it to take control of it. The Lure can then be charged by either letting it absorb a nearby Eidolon Vomvalyst's spectral form, or by picking up the energy orb they drop (indicated by a blue beacon) and passing it onto the Lure. Each lure needs the energy of three Vomvalysts to fully charge. It is recommended to have three lures under control by the end of the hunt.
  • Phase 1: The Eidolon Hydrolyst's shield can only be damaged with DmgVoidSmall64.png Void damage; this can be done with the Operator's power (unlocked only after The War Within). The Synovia weak points will be vulnerable once its shields have been depleted.
  • Phase 2: Take down Synovia; this will trigger an energy spike of 5 DmgMagneticSmall64.png Magnetic waves in a 65-meter radius and yield an Exceptional Sentient Core for each one destroyed.
    • With no charged Lure: The Hydrolyst will teleport away, regenerating 75% of its shield.
    • With at least 1 charged Lure: The Hydrolyst will not teleport away, regenerating only half of its shield.
  • Phase 3: Once all Synovia have been destroyed, the Hydrolyst will call upon surrounding Vomvalysts to heal it. Destroy these with the Operator.
  • Phase 4: The Hydrolyst's entire body will finally be vulnerable to damage. At this point it can be defeated.
    • With 0-2 charged Lures (Killed): The Hydrolyst will collapse to the ground, yielding only five Eidolon Shards and an Arcane Enhancement.
    • With 3 charged Lures (Capture): The Hydrolyst will be absorbed and dissolved into the ground, the Lures tethered to it explode, additionally yielding a generous amount of Sentient Cores, two Brilliant and Radiant Eidolon Shards each, two Riven Transmuters and draws from a different drop-pool of Arcane Enhancements.
    • Capturing an Eidolon Hydrolyst reimburses the previously sacrificed Radiant Eidolon Shard.
    • When captured, the Hydrolyst may also drop an Eidolon Hydrolyst Articula, which can be placed in the orbiter for decoration.
    • Successfully capturing the Teralyst, Gantulyst, and Hydrolyst in a single night yields a total of 2 Riven Transmuters, 2 Radiant Eidolon Shards, 3 Brilliant Eidolon Shards, 9 Eidolon Shards, 17 Flawless Sentient Cores, 15 Exceptional Sentient Cores and a large amount of Intact Sentient Cores.


  • Mod TT 20px.png Shattering Impact can remove the Hydrolyst's armor, even while it's shielded; 25 hits will remove the Hydrolyst's armor entirely, though doing so will also remove its weakness to DmgRadiationSmall64.png Radiation damage. It is advised to hit it only 24 times to allow for DmgRadiationSmall64.png Radiation damage to deal bonus damage to the Alloy Armor that it has.
  • The increasingly chaotic nature of the Hydrolyst's attacks, coupled with the giant's increased speed, makes attacking its weak points harder than ever, while enduring increased counts of hardly-avoidable damage. Prioritize the shoulder and armpit Synovias first as they are the most difficult to target.
    • Extensive use of defensive abilities, such as Trinity's Blessing and Oberon's Renewal will vastly increase the squad's survivability. Alternatively, one player with Unairu's Void Shadow and Void Chrysalis can cloak nearby allies while also greatly shielding them from damage. Yet another option is to have one of the operators use Vazarin's Protective Dash: when void dashing through an ally, it can heal up to 60% of HP in 5 seconds while rendering target invulnerable for that time. As it works on Warframes, Operators, companions, Sentinels and Lures, skilled use of Protective Dash can vastly improve the survivability of all allies.
    • Mod TT 20px.png Adaptation and the Umbral set of Mods will tremendously assist in surviving the Hydrolyst's constant barrage of area damage.
  • Bringing Squad Energy Restores is very much appreciated, as the Hydrolyst is capable of creating pulses of magnetic energy with its EMP Bubbles attack which both do extreme damage and proc DmgMagneticSmall64.png Magnetic. Besides the greatly increased damage, they function identically to Energy Spike, and can be avoided in the same ways.
  • The Granmu Prism is recommended for taking down this hulk, as the Shwaak Prism's fall off range isn't efficient enough to do significant damage as he moves around marginally faster than his counterparts, and is much larger. For players using Madurai's Void Strike, the best scaffold to maximize the damage output would be Shraksun Scaffold, while Unairu players can utilize the Klebrik Scaffold to dispatch the Vomvalysts with ease.
  • The near-constant and massive inflow of Vomvalysts in the latter stages of the fight gives a notable edge in battle to the Hydrolyst, as using his Summoning or Regenerating Scream will either vastly enhance the strength and diversity of their attacks, or grant the Vomvalysts a large amount of shields while they replenish the Hydrolyst's own shields. As such, it is imperative to kill as many Vomvalysts as possible to minimize this threat.
  • Taking an OberonIcon272.png Oberon equipped with the mod Mod TT 20px.png Phoenix Renewal with you greatly increases your effectiveness as the Hydrolyst has many magnetic proc abilities that Oberon's HallowedGround130xDark.png Hallowed Ground ability can disrupt. Mod TT 20px.png Smite Infusion can also be cast on squadmates to boost their Radiation damage output, thus exploiting the Eidolon's weaknesses.
  • VoltIcon272.png Volt's ElectricShield130xDark.png Electric Shields can be deployed to enhance both the Operator and the Warframe's damage. Be warned, however, that the Hydrolyst moves much faster than its counterparts and can quickly get out of range, drastically limiting the shields' effectiveness if not deployed often enough. Volt is also highly vulnerable to the Hydrolyst's attacks due to not having any damage mitigating abilities of his own, so he will likely require heavy support from other Warframes with healing abilities. Shock Trooper augment can also be cast on squadmates to boost their damage output with electricity. As bonus electricity damage can combine with existing elemental damage, weapons with existing fire damage will get radiation damage, thus exploiting the Eidolon's weaknesses.
  • ZephyrIcon272.png Zephyr can virtually ignore all of the Hydrolyst's attacks while also being able to shoot down its weak points with greater accuracy. This can be achieved by casting Turbulence to deflect all incoming projectiles, then charging Tail Wind to hover above the ground, thus dodging ground hazards and getting a clear view of the Hydrolyst's weak points.
  •   If Helminth infusion is available, several options to further boost warframe performance for eidolon hunt are possible.
    • Volt's Shock can be subsumed and infused into Oberon, replacing the Reckoning, which is not needed for Eidolon hunt. That way, a single warframe can provide both buffs, increasing the total damage buff available for the squad. An opposite infusion is also possible with Oberon's Smite replacing Volt's Discharge.
    • Other damage or attack speed boosting abilities, such as Roar or Warcry can be infused into warframes used for Eidolon hunting to get the most out of squad's performance.
    • Alternatively, helminth's innate Empower can be infused into frames responsible for buffing damage or healing to give them an option to further boost their ability strength by 50% when necessary.


  • Eidolon in Greek literature are the apparitions of living or dead beings.
  • Eidolon Synovias are a direct reference to synovial joints, which are compound joints found throughout the body.
  • Hydro is Greek for water.
  • The Eidolon Hydrolyst was placeholder-named as "Rainalyst" during development and is still referred to as such in the game's files.
  • Eidolon Hydrolyst is sometimes referred to by the community as "Harry".
  • The 3 night bosses of Plains of Eidolon together are sometimes referred to by the community as "Tridolons" (i.e. "Three Eidolons" - Eidolon Teralyst, followed by Eidolon Gantulyst, and finally by Eidolon Hydrolyst).


  • Even if you have charged lures to prevent the Eidolon from teleporting away, there is still a chance that it will teleport away.
  • Void blasting its legs sometimes will not spawn Unairu Wisp, however void blasting its upper body will always work.
  • The Eidolon Hydrolyst may sometimes be killed even with 3 charged lures, randomly ignoring one. Adding additional lures can prevent this.
  • When capturing the Eidolon Hydrolyst after Day begins, it may play the 'kill' animation and declare that the bounty has failed, but it will still drop shards as though it was captured.

Patch History[]

Update 30.9 (2021-11-11)

  • Fixed Eidolons being forcibly moved with Bonewidow’s Firing Line ability. While this may sound harmless, a full squad of Bonewidows could displace the Eidolon into water instantly spawning multiple Vomvalysts.
  • Fixed script error with Eidolon fights.

Hotfix 30.5.3 (2021-07-09)

  • Fixed all enemy shockwave type attacks doing knockbacks (ex: Eidolons).

Update 29.2 (2020-09-29)

  • Fixed a script error when playing Eidolon hunts.

Hotfix 27.3.15 (2020-04-17)

  • Fixed an issue where an Eidolon Wail could hit players in Limbo’s Rift after a Host migration.
  • Fixed a script error that could occur when fighting Eidolons if an energy wave was still propagating as the Eidolon died.

Hotfix 25.7.6 (2019-09-18)

  • Fixed Teralysts (and other Eidolons) taking more damage to weak points than they should be.

Hotfix 25.7.3 (2019-09-03)

  • Fixed certain Amps no longer applying multiple instances of damage to Eidolons. This resulted in the Shwaak Prism feeling like it lacked punchthrough, when in fact it was the Eidolon who was not registering hits.

Hotfix 25.1.1 (2019-06-06)

  • Fixed the Hydrolyst being affected by abilities that the Teralyst is immune to (e.g. Magus Anomaly).

Hotfix 23.10.6 (2018-10-18)

  • Improvements towards Vomvalysts spawning underground while fighting the Hydrolyst.

Update 23.10 (2018-10-12)

  • Fixed blinding Eidolon fights among other things by making sure adaptive exposure was working on all FX in dark settings.
  • Fixed an issue with missing Affinity when destroying an Eidolon Synova while not in Operator mode.

Update 23.0 (2018-06-15)

  • Hydrolyst no longer has regenerated Shields immediately after teleporting from being stuck.

Update 22.16 (2018-03-15)

  • Based on feedback we are making some changes to the intensity of Visual Effects in Warframe, especially in the context of Eidolon fights!
    • Reduced some visual noise/lens flares on numerous Warframe abilities.
    • Reduced some visual noise/lens flares on the Operator Amp explosions/melee burst.
    • Greatly toned down lens flare brightness and durations of Teralyst abilities (and variants) to help with visual clutter
  • Fixed an extra "0" damage number popping up for every instance of damage dealt to a Teralyst Synovia. Shotguns will therefore no longer shower the Teralyst with a confetti of zeroes when hitting a weak-point.
  • Fixed dealing slightly less damage to Eidolon Synovias due to obscured hitboxes.
  • Fixed a script error when being attacked by certain abilities from the Gantulyst or Hydrolyst.
  • Fixed replication issue preventing Clients from seeing the explosions from Hydrolyst's bubbles.

Hotfix 22.13.2 (2018-02-16)

  • Teralyst, Gantulyst and Hydrolyst now all drop Arcanes!
    • All 3 Teralysts have a 100% chance of dropping an Arcane.
    • The variety of Arcanes have been spread out across all 3 variants and weighted according to the rarity of the Arcane and difficulty of the Teralyst variant.
    • How you choose to defeat the Teralyst variants also attributes to the Arcane type/chance.

Hotfix 22.13.1 (2018-02-15)

  • Fixed a potential script error when fighting the Teralyst that would break Eidolon Lure functionality.
  • Fixed smaller than intended collision shapes on the Teralysts, especially noticeable on the Gantulyst and Hydrolyst. This did not affect their "damage hitboxes", only player collision.

Update 22.12 (2018-02-09)

  • Introduced.

Last updated: Hotfix 25.1.1 (2019-06-06)

See also[]