| Category | voidship life support/movement |
| Type | organism |
| Native | Void |
| Cost | 250,000 GP |
Void essences are organisms that reside within the Void. A skyship is classified as a voidship if it possesses a void essence. Through a symbiotic association, these organisms can sustain a habitable environment for those aboard ships venturing beyond a planet's atmosphere.
Void essences are challenging to locate and even more arduous to preserve when extracted from their native environment. This scarcity is the primary reason voidships are so costly. The quantity of void essences necessitated for a vessel depends on its size, with the general guideline being one void essence per 500 tons of ship weight (a ship-of-the-line, predominantly constructed of wood, averages 1,000 to 1,500 tons). A single void essence can sustain a habitable atmosphere for 50 medium-sized humanoids.
When removed from their natural living environment, void essences are housed in an airless enclosure. This is necessary because these creatures subsist on trace amounts of oxygen in their native habitat. If exposed to an oxygen-rich setting, they overindulge, explode, and perish. These explosions can be lethal and severely destructive to the surrounding area, necessitating extensive shielding to protect them. However, this protection cannot be too confining, as they still require sustenance. Their appetite increases when utilized to power a ship's void movement and the vessel's atmosphere. The mechanism by which they can provide oxygen for the ship without being killed by it remains incompletely understood. One theory suggests that the carbon monoxide released from the breath of living creatures alters their preferred food source to something they find even more desirable than oxygen.