Beings formed from debris, fragmented souls, and the bones of those that have fallen into this world. When created, they will grow flesh in a warped mirror of how they'd have looked when alive. After a set amount of time, known only to them, they will seek the place they were created and allow themselves to rot. The process feels similar to sleeping. When they are comprised only of bones and other dry materials, they will continue about their life until the pull comes again, and they leave to regrow their flesh.
Rarely, this cycle will be disrupted, and the demon is unable to complete the transition from one to another. This renders them mortal. In this world, one must die in order to live, and the reverse is true. Without death, there is no life for them.
Worm-like creatures that share a hivemind, and come together to form superorganisms. They will incorporate objects in the environment such as sticks to bulk up their form and mimic other beings. Prey is quickly engulfed and digested externally.
(More to come!)