The rejoice of fans everywhere, Blizzard is finally allowing for account-wide essences in World of Warcraft. In an expansion like Battle for Azeroth, where there has seemingly been one thing or another that has made players upset, the essence mechanic is one that definitely stands out.
If you're unaware of how essences work in Warcraft, they work with the Heart of Azeroth, a mechanic introduced in Battle for Azeroth by adding powers and boosts. These essences are essentially a required commododity in World of Warcraft, so earning them on more than one character can be incredibly time consuming and taxing for players who run alts.
Blizzard announced via a forum post yesterday that the team is bringing account-wide essences with the next server maintenance, effectively opening an avenue to unlock the essences on alt characters more quickly.
With the next regularly-scheduled weekly maintenance in each region, players who have earned a given Rank 3 Essence on one character will be able to directly obtain that Essence from MOTHER on any subsequent characters.
When playing an alt character that is missing Essences that have already been earned on a different character, most ordinary Visions of N’Zoth activities, such as Horrific Visions, Assaults, raid bosses, Mythic Keystone Dungeons, or BFA Season 4 PvP, will award a new soulbound currency – Echoes of Ny’alotha. These Echoes can be brought to MOTHER in the Heart Chamber, and exchanged directly for eligible Rank 3 Essences. While ordinarily each specific Essence must be learned in order to unlock it for other characters via MOTHER, all Essences associated with Nazjatar and Mechagon reputations will be available if any other different character has earned any of the Essences available from that reputation.
Essences on your alt characters will still require some grind as you'll need to get the currency to unlock them, and in doing so Blizzard states will "preserve the efforts that players put into unlocking a given Essence through its associated activity the first time."
You can check out the full post on the World of Warcraft forums.