Fiends are a species of creature born from a large amount of strong emotion in one area. The feeling that brings a Fiend to life, is also what that Fiend feeds on.
Fiends take the form of an animal or other living creature in the area they are born in in order to attract a caregiver to raise them, though there is often something about their appearance that is "wrong" somehow. This "wrong" feature is most often taken from an animal they are not trying to emulate, such as rabbit ears on a deer-like fiend or antlers on a dog-like fiend. Fiends' eyes also always have black sclera.
Fiends are born when a significant amount of one emotion is felt in one area by an abundance of people. Fiends take on the form of an animal or other living creature in the area in order to attract a caregiver to raise them. Fiends age at the same rate as whatever creature is caring for them. A Fiend left to its own devices may never age at all. Despite many Fiends taking the forms of wild animals, all Fiends maintain a level of sapience equal to that of Earth's Animal Folk. Fiends are rarely raised by other Fiends, but when they are, their aging instead depends on the other non-Fiend influences around them. If two Fiends are truly alone together, they stop aging just as if they were alone.
In adulthood, a Fiend’s aging becomes dependent on whoever or whatever they are most emotionally attached to.
Whatever emotion a Fiend is born from is also the emotion they consume. While any example of a Fiend’s specific emotion can be consumed, it is particularly fulfilling when that emotion is felt towards the Fiend personally. A Fiend’s emotion is not known to them innately and must be found out through trial and error. Some Fiends never figure out what their emotion is.
Because Fiends depend on other creatures to age and survive, they are rarely found only among other Fiends and some may never meet another Fiend in their lifetime. Some Fiends never even find out that they are a different creature than those they were raised by and around.
Many Fiends travel to, and sometimes choose to live in, the world of Infallis where Fiends make up a large portion of the population. In Infallis, Fiends are more likely to be found in groups together and are known to aid each other in finding out what their personal emotion is.