“ A swamp witch that, when she dies, a huge black worm burst from her corpse and tries to burrow into the nearest living creature to use as a new host. If the the worm is injured in-between hosts smaller black worms swarm out of any wounds and burrow into anything living.”
“ All spell casters gain their abilities through a form of demon possession. So in order to gain magical abilites, PCs must track down and trap demons. Of course there are some pretty powerful demons, if the demon is stronger than the PC, the PC could find themselves subjugated to the Demon's will.”