Furnerico

A mass of undulating tendrils and nerves, furnericos stalk sewer systems below large cities, reveling in the filth and rotting detritus created by those who dwell above the middens and sumps they call home. Fortunately for sanitation workers and other civil servants who ply their trade in sewer tunnels, furnericos are exceedingly rare and solitary. Their power is such that once one moves into a sewer system, it's often easier for urban planners to simply abandon that section to the monster and rebuild around it. A furnerico left to its domain like this is generally content to remain—as long as the filth keeps flowing.

Furnericos are asexual, spawning a single offspring as they expire from natural causes. One that dies by violence does not perpetuate its kind, presenting a vexing question to sages: where do these creatures come from, and why haven't they gone extinct over the ages?

Cultist Creations

The answer to "where are furnericos from?" is known by only a few, for it lies with the faithful of the parasite god Ghlaunder. These cultists use obscure rites to create furnericos from the very filth the monsters wallow in. Ghlaunder worshippers often do so to create powerful guardians for their hidden temples; furnericos created in this manner instinctively treat worshippers of Ghlaunder as allies... a trait not shared by those born from a prior furnerico, and a lesson many Ghlaunder cultists only learn moments before their death after assuming otherwise from a furnerico found in the wild.