Earth Essence
From Hades 2 Wiki and Guides
Useful Pages:
Nocturnal Arms, their Aspects & Upgrades
All the Boons
Hades II Guides
Earth Essence is usually gained from boons, and is needed for Infusion Boons.
Currently, Earth Essence is used for the Infusion Boons of Demeter, Hephaestus, and Hera