Many items in Dark and Darker can give an adventurer a headache, with Grave Essence being one of the most important. It can sometimes be found by killing Mummy or Zombie enemies, and can come in various rarities, but despite its appearance, not many players know what it is for.

Grave Essence currently has no use in Dark and Darker and can only be sold to the Collector in the Merchants tab for gold coins.

Adventurers believe that the item, like Maggots, could eventually come in handy, either for crafting or questing, but right now it only exists to sell (like many other items). Given how little it costs, there’s little incentive to pick it up, so save the item slot for something more valuable when you’re on a dungeon run.

Many items currently do little more than sell, but there's no telling if that will change in a future update, so feel free to keep a few if you want.