vDoM HM is not particularly hard--it's easier than vFV HM and many of the HMs that have come before it. But it is not friendly to healers.
Mechanic 1: Purification. Every member of the group takes Purification damage once the final phase of the boss fight starts. Purification ticks every 5s and is unavoidable. The damage from Purification increases over time. Initially, Purification doesn't do much damage, but if you take too long, the damage ramps up until it gets so high that it just wipes the group.
Mechanic 2: Periodically, the boss will plunge all four swords into the ground. Everyone except the tank will receive an effect called Decrepify. This unpurgeable affect lasts for 5s, does Oblivion Damage equal to 10% of a player's max health every second, applies an extreme (almost 100%) defile, and snares the player.
The ramping Purification damage means that this fight is a DPS check. If you have a third DD and can nuke the boss down quickly, then Purification never becomes a threat.
By itself, Decrepify is mostly a nuisance. But it is quite deadly when combined with other sources of damage. Since it is Oblivion Damage, it cannot be mitigated or shielded, so is guaranteed to eat away 50% of your health. If you happen to have less than half health when Decrepify begins or if you take a large chunk of damage while you have Decrepify, you are guaranteed to die, since the near totality of the defile means that a healer cannot help you.
When we worked on the Depths Defier trifecta achievement last week, we came to the conclusion that we didn't want a healer. Having a third DD meant we could avoid high Purification damage, and the moments when we were most vulnerable--when the Decrepify is active--were also the moments when healing was entirely useless. Fortunately, our healer could easily swap between DD and healer roles. He put on some emergency off-heals, and we got Depths Defier with a 3x DD setup.
Again, vDoM HM is not particularly difficult. But it is pretty anti-healer. I also do not want to advocate a change in the mechanics, though--any nerfs to the DPS race or the defile would make this HM even easier than it already is, since the combination of Decrepify, high Purification ticks and other damage is the only real challenge to this boss fight. But, in the future, let's give players challenges where healers can actually play a role.
Edited by code65536 on March 4, 2019 7:18PM
Nightfighters ― PC/NA and PC/EU
Dungeons and Trials:
Personal best scores:
- Dragonstar Arena: 46817 (NA)
- Maelstrom Arena: 600526 (NA)
- Blackrose Prison: 99274 (EU) (Unchained)
- Maw of Lorkhaj: 165227 (EU)
- Halls of Fabrication: 220708 (NA) (Tick-Tock Tormentor #1, #2, #3, #4, #5, #6, #7, #8, #9, #10, #11, #12)
- Asylum Sanctorium: 114957 (NA) (Immortal Redeemer #1, #2, #3, #4, #5, #6, #7, #8, #9, #10)
- Cloudrest: 131256 (NA) (Gryphon Heart #1, #2, #3, #4, #5, #6, #7)
- Sunspire: 250866 (EU) (Godslayer #1, #2, #3, #4, #5, #6, #7)
- Kyne's Aegis: 235841 (EU) (Dawnbringer #1, #2, #3, #4, #5, #6, #7, #8)
Dungeon trifectas: