History of Essence of Anguish

Overview

This is one of the Nightmare Essence quests from Shadowkeep. It is a Eris Morn / Lectern of Enchantment quest: you buy the Essence at the Lectern in Sanctuary on the Moon, cleanse it by completing the objectives below, then return to the Lectern to turn it into gear. Expect a few days: it needs three daily bounties. Sources describe the Essences as costing one Phantasmal Core each, and objectives only need completing once per account (later identical Essences auto-complete those steps). The quest was part of Season 8 content; I could not confirm from the sources whether it has since been removed or vaulted, so check in game.

Walkthrough

1. Pick up the Essence of Anguish from the Lectern of Enchantment in Sanctuary.
2. Complete 3 daily bounties from Eris Morn (one per day is the practical limit, as bounties refresh daily).
3. With the Essence cleansed, the game tells you to work with Eris Morn to find a solution; talk to her to progress.
4. Visit the Lectern of Enchantment in Sanctuary to infuse her magic with Nightmare Essence and create the gear.

Rewards

Leg armor for your class: Dreambane Greaves (Titan), Dreambane Strides (Hunter), Dreambane Boots (Warlock).