The Jeeven are a hunter-species.
The Jeeven have two forms. When a Jeeven has no host, "Hostless", it is shaped like a spiked mace, heavy on the spiked side, and glows with a light which changes color based on its urgency to find a host. When a Jeeven has found and subdued a host, using its hypnotizing light, it enters the "Engaging" form over its hosts face, in which it liquifies its body and spreads over the face of its prey, finally solidifying into a perfect, transparent mask over the face of its host. In this way, the Jeeven is able to feed on its host's Light force over a longer period of time, a method which allows the Jeeven to use up that Light force slower than if it instead devoured the Light force instantly. While the Jeeven feeds on its host, the host continues its normal activities, growing weaker and eventually dying- the younger a host is, the longer it can generally survive while feeding a Jeeven, but a host always dies much younger than its peers.
There have been some reports of a manipulated or perhaps even sentient type of Jeeven; for more on this type, see Jaeven.