Ectoplasm
Ectoplasms were blob-like, bioluminescent parasites. They could be found all across Legere, although they were far more common in colder regions. In Corgath, it was common to find ectoplasms gathering in basements and storage structures.
Ectoplasms on their own were completely harmless. An individual could touch or even ingest the creature without consequence. However, they became dangerous and problematic if they came into contact with a corpse (human or other). Ectoplasms infested dead bodies (colloquially called possession) and animated it by distributing itself throughout the remains. They attached themselves to the skeleton, and would slowly dissolve the remaining flesh for nutrients. Ectoplasms would also use the body to attack and kill prey which they could transfer themselves into. This was the only way ectoplasms can reproduce; once enough mass was digested from corpses and they were large enough, they would shed a portion of their gel-like body. The shed portion would go on to seek out more dead bodies. Hence, ectoplasms were required to find, kill, and digest more prey in order to reproduce.
Possessed creatures were easily identified, as their bodies were rotted, and the ectoplasms’ teal coloured, glowing slime was visible "filling in the gaps" in the body. It was possible for a dead creature to be possessed by multiple ectoplasms but needed the body of a substantially large creature. Ectoplasms could possess mollusks and other boneless creature, but would not be able to use the body once majority of its flesh has been digested.
Salt water was irritating for ectoplasms, ensuring that marine life or waterlogged corpses in the sea were never possessed.
As ectoplasm infestations could spiral out of control quite rapidly, a guild of hunters was formed out of Corgath known as the Ghosthunters. They utilized special tools to eliminate ectoplasms (which could be a challenge to take down if they were inside a tough host). Their weapons used specialized, semi-magical stone tips/blades that caused ectoplasmic entities to shrivel up.