The Venomous Abyss opened on August 18. Five weeks later, its final boss is still being tuned, and the September 21 hotfix is the largest single change yet: Ula'tek's Stone Venom damage reduced by 40% on all difficulties, applied with weekly restarts.

The same pass promoted Boiling Venom to an Important Aura on Mythic, and fixed a case where Stone Venom could fail to damage players standing far from the boss. The second of those is a bug fix disguised as a buff. The first one is a straight admission that the encounter's damage check was priced wrong.

The 40% is the headline, but the pattern is the story

Tracking Ula'tek's hotfix history gives a clearer picture than any single number. This is the fourth pass on the same encounter:

Every one of those entries is about the same thing: what happens to this fight when the number of people in the room changes.

The raid-size problem, explained

The clearest example is Spectral Coils, which the August 20 hotfix had to stop from scaling with group size on non-Mythic difficulties. Head Topics broke the mechanic down at the time: the ability is a stack-up-and-soak effect that reduces its damage by a flat percentage rather than splitting it between players, while simultaneously growing by roughly 10% per additional raider.

The arithmetic that follows is brutal. Around 680,000 base damage, reduced by 50% when the raid stacks, comes out survivable in a small group. In a 30-player raid the same ability lands near two million, and the stacked reduction brings it back to about one million — enough to delete most of the raid. The bigger your roster, the less likely you were to kill the boss, which is the exact inverse of how raid scaling is supposed to work.

Blizzard's fix removed the group-size multiplier on Normal and Heroic and required 40% of the raid to be stacked for a full reduction. By September the remaining tuning target was raw damage, not scaling.

That is the context for a 40% cut. It is not a difficulty pass aimed at making the raid easier for everyone; it is the last step of unpicking a design where raid size acted as a penalty. And the Mythic aura flag matters for a different reason: promoting Boiling Venom from an untracked debuff to a tracked one changes the encounter from a memorisation test into a coordination one, because healers and raid leads can now see it in the default interface.

Why this tier was always going to need a second pass

Three things made the Venomous Abyss unusually hard to land on the first try.

Patch 12.1 raised player health and creature damage by 25% at max level and redistributed throughput out of burst cooldowns into steady damage. Any encounter tuned in the same window as a global 25% health change is being tuned against a moving floor.

Season 2 opened two weeks after the patch, not with it — August 11 for the zone, dungeon and housing work, August 18 for the raid itself. That compresses the feedback window between patch notes and live raid nights.

The endgame is being split across two updates. The Venomous Abyss is Midnight's current tier, and 12.1.5 is bringing something structurally different: the single-boss Unbinding of Kith'ix raid, which is on the PTR now. A one-boss raid with a shorter clear is a very different tuning problem from an eight-boss instance, and it suggests Blizzard is deliberately varying the shape of endgame content rather than repeating the same format.

The other half of the September 22 pass

The September 22 hotfix was mostly a class-tuning post — we covered the ability changes in our Midnight class tuning briefing — but it also carried a healing-trinket and stat-stick rebalance that matters for anyone raiding this tier:

Read together, the list is a correction of a badly weighted trinket tier: the healing options were too weak to compete, and three stat-stick trinkets were overperforming enough to be cut by 10–25%. The Ruby Whelp Shell change is the most aggressive single line — it doubles the trigger rate while cutting damage by 42% and halving the stat effect, which is a redesign rather than a number tweak.

What to take from it

• Mythic raiders should expect the fight to feel different, not easier. A 40% cut to one ability plus an aura flag changes where the failure points are. Guilds mid-progression may find the mechanic they were wiping to is no longer the one that kills them.
• The tuning is not finished. Five weeks, four passes, and 12.1.5's PTR still running. Anyone treating current Mythic difficulty as the tier's final form should plan for at least one more swing.
• Trinket rankings are provisional. If you have been holding a healing trinket on the bench, this is the week to re-test it rather than trust a list written in August.
• The size of your raid matters less than it did. That is the real outcome of five weeks of patching here, and it is worth stating plainly: raid-size scaling was the bug, and the current baseline is closer to the design intent than the version players met on August 18.