Luminessants are small orbs of light, referred to as "creatures", seen in Haunting Ground. Fiona Belli describes them as "lightning". They function as "Azoth detectors" as they respond to the ethereal energies of the Azoth, and will hover towards Fiona if she is nearby. If they touch her, they will produce a charge that shocks Fiona and raises her panic and attract stalkers. The greater the Azoth in the carrier, the more powerful the shock is. Luminessants can be helpful as they are used twice in the game to solve puzzles in the Old Mansion.
Their lifespan decreases in contact to open air; it differs from specimen to specimen, but it is never more than a few minutes. Luminessants will die faster if the player lures them into open areas, but at most circumstances, it's better that the player finds a neighbor room and closes the door to cut off their tracking sense.