This pure black, oily fluid must be kept in tough, light-proof containers, since it is destroyed after one turn in bright sunlight or one hour if exposed to daylight. Essence of darkness is pure, concentrated, liquid darkness itself. It can be used in a number of ways:
- When a dose is swallowed it makes the imbiber's entire body, including hair, teeth, and even the whites of the eyes, pure matte black in color. This can enhance a thief's chance of hiding in shadows as shown below.
- Similarly, if one dose is diluted in a gallon of warm water, the essence creates a powerful black dye. A gallon of the diluted form can be used to dye clothes and even armor and weapons; one gallon of the dye is sufficient to treat the clothes and equipment of one character. The dye takes one turn to mix and soak into the items and one turn to dry. This process also affects the chances for successful hiding in shadows.
| Body only (wearing normal clothing) | +5% |
| Body only (wearing no clothing) | +25% |
| Clothing only | +20% |
| Both body and clothing | +40% |
These bonuses only apply when the thief is trying to hide in darkened areas or attempting to hide in shadows. Detection resistance operates on a thief using essence of darkness to hide in this way.
Essence of darkness is unstable and if a vial is struck by a crushing blow it explodes into darkness 15' radius. A single dose of the magical essence creates a darkness 5' radius if struck.
This property was exploited by making small glass or ceramic globes filled with the liquid, which are then thrown forcefully onto hard surfaces to create darkness bombs. At the DM's option, a thief who has ingested the essence or applied it to his or her clothing might similarly become the center of a darkness 5' radius effect if struck a severe blow with a blunt weapon (50% of remaining hit points, with a 12 hit point minimum for the effect to operate).
The effects of essence of darkness last for six hours plus 1d6 turns, if used externally; if ingested, it has the same duration as a standard potion. Each bottle or vial of the essence found usually contains sufficient fluid for 1d4+4 doses.