Fiend

A fiend was an evil creature from one of the Fiendish Planes. They were not just evil, but born of evil; primal malevolence was one of the roots of their nature, and the evil essence of the fiendish planes permeated every part of their bodies.

Description
A fiend was a creature from the Lower planes. This did not mean that every single creature from the Lower planes was a fiend. Only baatezu, gehreleths, hordelings, tanar'ri, and yugoloths were actual fiends in the narrow sense. In the broader sense, every outsider with evil as part of its being was a fiend.

The life expectancy of a fiend was not known. An observation about their aging process was that they did not mature. Those fiends that reproduced, gave birth to smaller version of their species that grew bigger and stronger with time, but a fiend dying of natural cause or just growing old was never observed. However, it was assumed that they were immortal. One unique feature about them was that they changed from time to time into a different form. However, this was merely changing into and not some form of metamorphosis.

Personality
Fiends lived long and were capable of having an inhuman view on time and life. They were capable of viewing a century passing by as inconsequential.

True Name
Every creature had a true name that made it possible for other creatures with knowledge of it to gain control over the creature whose true name they know. For fiends, the true name was a double edged sword. Knowing it made it possible for a fiend to rise up the fiendish ranks, something that is very difficult for fiends who did not know their own true name. On the other hand, if the knowledge about the true name somehow spills out, the fiend handed over other creatures control over it. This control extended very far. For example, a mortal knowing the true name of a fiend could not just call it from the Outer Planes to the Prime Material plane using the true name but also force it serve the mortal by using the same true name. To hurt their rivals, fiends often tried to find out their rivals' true names to spread the knowledge among mortals, so these could force them into servitude.

As mentioned above, a fiend needed knowledge about its true name to rise up the fiendish hierarchy. It often happened that the true name became different on changing form. It was believed that this was not the true name changing but some form of evolution of the true name. The core of the true name remained the same but there were some additions to it. When a mortal used an outdated true name to bind a fiend, the fiend responded to the binding. However, the control the mortal exhibited over the fiend was not complete and this could have fatal consequences for the mortal.

Mortals
Mortals and the worlds they live on were seen as useful things, this did not mean that they viewed mortals as having any intrinsic value. The value of mortals lay in their future potential of turning into fiends on dying, when they were evil. To do this, mortals were exposed to temptation by the fiends. Otherwise, mortals' value, as far as fiends were concerned, lay in their potential as slaves, playthings, food, and mercenaries. The Prime Material plane's value lay in its potential as a battlefield that was not protected because it had no outsiders that were dedicated to its protection. Its primary value however, lay in its potential as a generator of faith. When mortals started to respect fiends, for example due to their potential to terrorize them, fiends gained this faith and with it actual power.

History
The important event in fiendish history was the Blood War. The Blood War was an interplanar battle between demons and devils. This cost so many lives on both sides that they were forced to figure out how to refill their ranks in rapid fashion. The answer both sides came up with was to convert larvae into fiends. After they found out that larvae were what became out of the souls of evil people, they started to work towards turning mortals to evil.

Demons
Demons were the most widespread race of fiends. They were chaotic evil and were native to the Abyss. Tanar'ri, obyriths, and loumara were the three races of demons, but there were many other species as well.

Yugoloths
Also known as daemons, yugoloths were manipulative, neutral evil fiends native to the Blood Rift. They were secretive and mercenary by nature.

Devils
Devils were lawful evil fiends who hailed from Nine Hells of Baator. The baatezu were the dominant species.

Demodands
Also known as gehreleths, demodands were said to have been fashioned by one of the primal creations of Evil, exiled because of their chaotic taint. They dwelt in the Supreme Throne.

Archfiends
Archfiends were not actually a separate kind of fiend on their own, but rather a grouping of powerful, unique fiends of any of the above kinds. The most prominent groups were the archdevils and demon lords. Archfiends could be incredibly powerful, almost as powerful as true deities.

Half-fiends
Due to their magical natures, fiends were capable of breeding with most other creatures. The resulting offspring was called a half-fiend. Some such hybrids could breed true. Notable varieties of half-fiends included cambions, and draegloths.

Other Fiends

 * Achaierai : Creatures that looked like large, flightless birds with four legs.
 * Hell hounds : Fiends that looked like large, powerfully built dogs with rust-red fur, red eyes, and black teeth and markings.
 * Barghests : Shapechanging fiends native to Gehenna, barghests naturally resembled large, goblin-wolf hybrids with orange eyes and blue fur.
 * Larvae : Also called soul larvae, larva were the fiendish remnants of evil mortal souls.
 * Night hags : Merciless, horrible humanoid fiends with black skin, red eyes, skeletal bodies, clawed hands, and horns. Night hags also possessed powerful magical abilities.
 * Nightmares : Neutral evil fiends that appeared as large black horses with flame in place of a mane and tail, and flaming hooves.
 * Maelephants : Large, humanoid fiends with clawed hands and elephant-like heads. They were often employed by more powerful fiends as guardians of treasure.
 * Rakshasas : Powerful, sorcerous fiends from the lawful planes with animal-like heads and backwards hands.

Relations
The demons and the devils held an eternal enmity for one another as they waged the Blood War.