Hidden Potential of the Netherlord

To complete this achievement, you need to unlock one hidden appearance for your class. To be able to get a hidden appearance, you need to have the class hall unlocked and the base artifact for your spec.

Affliction
Hidden appearance is unlocked by using [item=139575]
First, you need to get [item=140764], which can drop from Eredar mobs (for example, [npc=107267] or [npc=90661]). Once you get the item, you will start a quest The Grimoire of the First Necrolyte, that will require you to obtain 13 [item=140762] that drops from DANGER world quests. It will take you a few days to finish.
Once you have the skulls, use them at the [object=254007] in the Deadwind Pass to summon [npc=112862]. Once you kill her, she will drop [item=139575].

Demonology
To get [item=139576] you need to kill Eredar on the Broken Isles and Argus and loot their skulls. The first 5 skulls will be grey items, the 6th one will be the hidden appearance.
Skulls drop in this order: 1) [item=140661], 2) [item=140662], 3) [item=140663], 4) [item=140664], 5) [item=140665], 6) [item=139576].
The best place to farm this is at Krokuun at Nath'raxas Hold. The area is quite small and the mobs hyperspawn, so unlike in other places (like Azsuna) you don't have to fly anywhere. Don't forget to loot constantly! /way #830 64.70, 25.79

Destruction
[item=139577] has a chance to drop from demons summoned with [spell=227892].
Speak with [npc=108018] in your class hall and research [order-advancement=366] (second row, left option). Then you can speak with [npc=111740] to start Ritual of Doom. You'll need 2 other players to start the ritual and you can find the Ritual of Doom spell in the GENERAL tab in your spellbook.. Don't forget to use soulstone on yourself, because one player will die at the start. Demon summoned by the ritual has a chance to drop the [item=139577].

Demonology one took only 10 minutes of killing mobs in the hyperspawn area.

21 February 2026
In order to get Visage of the First Wakener, one of the hidden appearances for the achievement and just to unlock the decor and after hours of farming only to realise:

You MUST have completed the quests to get the Demonology artifact weapon, Skull of Man'ari.
I got all 5 heads and the Visage in exactly 13 minutes after doing three quests:
Ritual Reagents
Looking into the Darkness
Dark Powers.

I wasn't in Demonology spec but had the weapon equipped for good measure. I went to Argus and flew to Hope's Landing in Antoran Wastes and went to a spot called Defiled Path and farmed the mobs around where Lieutenant Xakaar spawns. Got all of the first 5 heads very quickly and then the Visage.

I naively thought this would be as easy farm like other class hidden appearances. Don't be an idiot like I was and blindly farm for hours and hours. Go and get the artifact weapon and THEN go farm for the heads and visage.