What is Atrophic Poison
Atrophic Poison is more commonly known as "The Rogue Raid Buff," as it's one of the main reasons to try to have at least one Rogue in each raid composition. This ability is applied to mobs, making them deal less damage (4.8% in 12.1). While raid buffs can be 1a hard requirement, such as Death Knights on Dimensius, Atrophic Poison and Rogues have been skipped on multiple bosses, such as the World First Kill of Belo'ren.
Atrophic Poison Findings
In a video by Whispyr, he breaks down some of the recent findings from the Rogue community.
The most notable new finding is that Atrophic Poison works on some environmental damage. It was previously thought amongst many in the WoW community that environmental damage could not be reduced by targeted damage reduction effects, which includes Atrophic Poison, but it seems that this may have been incorrect or changed at some point. It seems that Blizzard is able to link environmental damage to a different entity, making Atrophic Poison and other abilities work. This means that on upcoming bosses such as Sszorak or Twin Fangs, which deal a large portion of environmental damage, Atrophic Poison is looking to be better than expected. In theory, this should also apply to similar abilities such as Demoralizing Shout from Warriors and Fiery Brand from Vengeance DHs.
The main issue that still occurs is that damage that sources from a "Named" NPC that is untargetable such as Xal'atath on Vael'gor and Ezzorak is still an issue for Atrophic Poison. There are a couple sources of this in next tier such as on The Lost Explorers.
Whispyr summarizes a portion of the video in the comments:
For a more technical overview of how this works, as far as we are aware currently:
1. Damage can be attributed to things that logs cannot/will not pick up on and parse correctly. Unclear if this is a log issue or a blizzard issue or both
2. "Named" NPC entities (like Xal'atath on dragons in Season 1, the Boxes on Explorers, Vashnik on Sentinels) are an issue for atrophic, as you cannot poison something you cannot hit
3. "Unnamed" NPC entities ("Environmental Damage"), CAN have its damage attributed back to a Named NPC entity. This is not always consistent, and needs to be investigated case by case
4. Currently the big "issues" with atrophic can be isolated to the first half of the raid, where it probably won't matter that much. The three hardest bosses that we know of (Sszorak, Twin Fangs, Coiled Altar) are all attributing correctly and atrophic works on those fights
5. Ula'tek is untested and we have no way of knowing if Atrophic has issues on this fight until we get logs to dissect
