In Embers of Neltharion, you must earn the Dragonflight Season 2 Hero achievement to unlock additional visual effects for Aberrus class set appearances.
Dragonflight Season 2 Hero requires players to complete one of the following achievements:
Dragonflight Keystone Hero: Season Two – Attain a Mythic+ Rating of at least 2500 during Dragonfight Season 2.
Elite: Dragonflight Season 2 – Earn the rank Elite during Dragonflight Season 2.
Mythic: Scalecommander Sarkareth – Defeat Scalecommander Sarkareth in Aberrus, the Shadowed Crucible on Mythic Difficulty.
Once you complete one of the achievements by participating in raiding, PvP, or Mythic+, you will receive Obsidian Aspectral Earthstone that unlocks additional visual effects for certain Aberrus, the Shadowed Crucible class set appearances. The unlock is account-wide, as the tooltip suggests.
There’s also an easier achievement called Dragonflight Season 2 Master that rewards 1 Draconic Mark of Mastery which you can turn in for 1 Heroic Aberrus Tier Set piece.
Patch 10.1 is releasing on May 2, 2023. The update is the first major content patch of the Dragonflight expansion, bringing exciting new updates to Dragonriding, a new raid, Season 2 content, a new underground zone, and more.