Cacodaemon

Cacodaemons are the lickspittles, toadies, pets, and soul batteries of daemonkind.  Their ability to trap the spirits of the recently departed in soul gems makes them a threat even when they are not a party’s primary antagonist.  And they are never not hungry…

A battle near a planar rift draws the attention of a swarm of cacodaemons.  They come boiling through the thin barrier between the planes, adding further confusion (and confusion spell effects) to the struggle.  The cacodaemons eagerly devour and digest the souls of the dead.  If they are not stopped, the sheer number of souls consumed will act as a beacon to larger daemons, night hags, and other terrors.

Just before he stumbled through a teleportation circle, the young rogue Wil Minchum was bitten by a cacodaemon in a dungeon halfway across the world.  Now suffering through cacodaeomonia, he has not had the Fortitude to free himself of the disease.  Worse yet, the cacodaemon’s monotonous telepathic conversation—“killyou eatyoursouls gobbleitup eateateat inthebellyyougo gobbleeatdie”—is driving him mad.

On the strand of a sun-baked colonial city, a piscodaemon runs a bizarre and deadly gladiatorial arena that sits open to the sea.  The many lizards and snakes that lurk in the sand—and even the octopi in the tide pools along the shore—are actually cacodaemons eager to snap up the souls of the fallen.

—Pathfinder Bestiary 2 64