Single-phase fight with two independent mechanics to handle in parallel.
The first are the Frost Orbs. Three players receive a debuff that leaves a trail of ice orbs behind them, twelve in total. If these orbs are left on the ground without being triggered manually they detonate, inflicting heavy burst damage and a stacking DoT on the raid. Every contact with an orb deals damage to the player who triggers it and increases the damage they'll take from the next orb by 15%, so it's worth assigning several players to the mechanic. Triggering an orb while immune applies no stack, a DPS with a defensive can take two or three in a row, and tanks can take them without trouble. Every orb triggered leaves an ice patch that makes characters slide, and the only way to clear it is the tank frontal, which must be aimed over the patches.
The second are the murlocs. Adds emerge from the edges of the arena and run in a straight line toward the bubble at the center of the room, ignoring aggro. If they reach it they transform into empowered versions that deal constant raid damage, so they must be stopped with CC, slows and grips. The water pools that appear on the ground tell you in advance how many murlocs will emerge at that spot.
The last mechanic worth noting is a set of vortices that periodically cover the entire arena leaving a single safe zone free, followed by a knockback originating from the central bubble, for which it's worth positioning so as not to end up beyond the edges of the arena.
| Difficulty | Item Level | Currency |
|---|---|---|
| World | 279 (Veteran 1/6) |  Veteran Mistcrest |
| Normal | 292 (Champion 1/6) |  Champion Mistcrest |
| Heroic | 305 (Hero 1/6) |  Hero Mistcrest |
| Mythic | 318 (Myth 1/6) |  Myth Mistcrest |
TL;DR
What to do
Everyone
- Every Chilling Frost: trigger the Frost Orbs by walking over them, gradually and on rotation. Never the same people back to back.
- Every murloc spawn: stop them reaching the bubble with CC, slows and grips.
- Raid movement: move to the group of 5 first, then the group of 3, then the lone murloc.
- ~1:10: get to the safe spot during Swirling Whirlpools, then stay in melee before the Pop! knockback.
Tank
- Every Water Jet: aim the jet at the ice patches to clear them. It's the only arena cleanup tool available.
- Watch the
Water Jet stacks, which increase damage taken from the effect by 20%.
Healer
- Every orb triggered: on Mythic this also fires
Frost Burst, ~216k on the whole raid. - Every Abyssal Rain: raid damage plus a residual DoT, and on Heroic and Mythic the boss gains +5% Frost damage cumulatively.
- With Berserkers alive:
Pulsing Tides deals ~494k to the whole raid every 3 seconds, per Berserker.
DPS
- Absolute priority on the
Bubblefin Frostscale (Mythic only): it shields the other murlocs by 99%. - Every
Abyssal Rain grants the boss +5% Frost damage, cumulative and non-decaying: the more cycles pass, the more lethal Shatter, Frost Burst and Pulsing Tides become. There's no reason to extend the pull.
What can kill you
| Ability | When | How to avoid it |
|---|---|---|
Stacked  Frost Orb | After Chilling Frost | Each contact gives +15% Frost Orb damage taken for 16 seconds, cumulative: rotate who collects |
 Lingering Frost | After each orb triggered | Constant damage and the character slides |
 Swirling Whirlpools | ~1:10 and each cycle | There is exactly one spot with no vortices |
 Pop! | End of the Whirlpools | Knockback: stay in melee to avoid landing in the water |
| Pulsing Tides | With Berserkers alive | Stop the murlocs reaching the bubble |
What wipes the raid
| Mistake | When | Consequence |
|---|---|---|
| Frost Orbs left untriggered | After Chilling Frost |  Shatter: ~525k on everyone plus ~185k every 2 seconds for 30 seconds, cumulative |
| Murlocs reaching the bubble | Every spawn | They become Bubblefin Berserkers and each one adds constant damage |
| Dragging the fight out | Cumulative |  Wavecaller's Might, then  Unending Tides |
Timeline
| Point | What happens |
|---|---|
| Cycle | Chilling Frost on 3 players, generating 12 Frost Orbs to trigger gradually. The tank clears the patches with Water Jet |
| In parallel | Water pools on the ground announce murloc spawns. The raid moves: group of 5, then 3, then the lone one |
| ~1:10 | Swirling Whirlpools, then Pop! with knockback |
| Then | The cycle repeats, not always from the debuffs: sometimes from the tank frontal |
Each Abyssal Rain increases the boss's Frost damage by 5%, cumulative. That's a soft enrage.
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Detail
Chilling Frost and the Frost Orbs
Three players receive a debuff, visible as an arrow above the head and on the raid frame. It deals periodic damage and −15% movement speed, and every tick leaves a Frost Orb at the player's position. PTR testing showed four orbs per player, twelve in total.
| What you do | What happens |
|---|---|
| Walk over them | The orb attaches: damage plus a DoT, and +15% Frost Orb damage taken for 16 seconds, cumulative. On Mythic this also fires Frost Burst, ~216k on the raid |
| Leave them | Shatter: ~525k on everyone plus ~185k every 2 seconds for 30 seconds, cumulative |
They must therefore be triggered manually, spreading the contacts across several players rather than concentrating them.
The debuff alone isn't the reason to go slow: an orb taken while immune applies no stack, and with a defensive you can still take two or three in a row. The risk comes from the combination — triggers too close together while the debuff and the area damage are both active. In some observed testing the deaths came exactly that way, with several players clearing quickly at the same time.
Every orb triggered leaves a Lingering Frost patch: constant damage and character sliding, exactly like Sennarth's pools.
Water Jet
A high-pressure jet on the tank's target: continuous damage and progressive pushback. Each hit increases Water Jet damage taken by 20%, cumulative for 40 seconds.
The jet washes away the ice patches: the tank must aim the line over the Lingering Frost.
On Normal and Heroic the tank instead receives 
Iceblade Flurry, sustained direct damage with no cleanup component.
The murlocs and the 
Alluring Bubble
Nymrissa gathers water into a bubble at the center that mesmerises the murlocs.
The murlocs have no aggro: they emerge from the water and run straight for the bubble, ignoring everything else. If they reach it they become Bubblefin Berserkers, which cast Pulsing Tides: ~494k Frost on the whole raid every 3 seconds for as long as they live.
CC, slows, roots and grips should be used freely.
The water pools on the ground show how many murlocs are about to emerge there: one pool, one murloc; five pools, five murlocs. Counting them tells you in advance where the heavy work will be.
On Mythic the large group includes the Bubblefin Frostscale, which projects a Waterfog Shield reducing damage taken by nearby murlocs by 99%. Any single-target damage on a murloc should always go to the Frostscale.
Raid movement: group of 5 with the Frostscale, then the group of 3, then the lone murloc, which is held in CC until the raid arrives.
Swirling Whirlpools and Pop!
Around 1:10 Nymrissa awakens vortices converging on the bubble, generating them from every point but one: that's the safe spot.
When the vortices reach the bubble it bursts, dealing raid damage and a substantial knockback. Without a way to cancel it, stay in melee: the closer to the center, the lower the risk of landing in the water.
Abyssal Rain and the soft enrage
A torrent of water from above: raid damage for 4 seconds plus a residual DoT.
On Heroic and Mythic each Abyssal Rain grants Nymrissa Wavecaller's Might: +5% Frost damage, cumulative. Every extra cycle makes Pulsing Tides, Shatter and Frost Burst proportionally more lethal.
If the fight runs long, Unending Tides arrives: a catastrophic surge dealing ~370k per second to the whole raid.
Two approaches to orb handling
| Approach | How | Pros | Cons |
|---|---|---|---|
| Free triggering | Trigger them where they land, gradually, following the murloc rotation | Simple and robust | Less tidy |
| Orbs at the edge | Orbs are always left at the edge of the arena | Concentrated, easy-to-clear patches | Murlocs can spawn on the ice patches, forcing work on slippery ground |
Adopted: the first. The tidy version introduces a real risk for a cosmetic benefit, and in PTR testing that's where the deaths happened.
Assignment checklist
- Trigger rotation for the Frost Orbs.
- CC assignments on the murlocs, particularly the isolated one.
- Marking the Frostscale.
- Tank aware they must aim Water Jet at the patches.
- Who calls the safe spot during Swirling Whirlpools.
- Reminder to be in melee before Pop!.
Loot
No tier set token.
The boss drops two armor pieces for each slot, plus various weapons, a ring and a trinket: 
Wavecaller's Seastone (trinket), 
Tidepiercer's Bubble Popper (staff), 
Bubblefin Splash Guard (shield), 
Frostscale's Mystic Frond (off-hand), 
Alluring Bubbleband (ring), 
Tidebound Sorcereress's Robes, 
Coiled Hex Legguards, 
Swelling Sea Spaulders.
Player housing decor can drop at any difficulty.
It counts toward the Raid slot of the Great Vault and is the only encounter of the season offering Flexible Mythic.
Achievement: 
Nymrissa Wavecaller · 
Heroic · 
Mythic
Guild Run versions of all three also exist: 
base, 
Heroic, 
Mythic. Running the group internally earns them at no extra effort.
Guild guide. Data verified on Wowhead. Analysis based on PTR testing on Mythic.
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