Fiend

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

Types of Fiends
The tanar'ri and the baatezu hold an eternal enmity for one another as they wage the Blood War.

Demons
Demons are chaotic evil fiends, native to the Abyss. Tanar'ri are the dominant species of demon, but there are a number of others.

Devils
Devils are lawful evil in alignment and hail from the Nine Hells of Baator. The baatezu are the dominant species.

Yugoloths
Also known as daemons. They are neutral evil in alignment and inhabit the Blood Rift.

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

Other fiendish races
While not all denizens of the Fiendish Planes are fiends as such, other inhabitants of the fiendish planes include:

Abyss

 * Abrian
 * Abyssal ant swarm
 * Abyssal ghoul
 * Bloodfiend locust swarm
 * Bodak
 * Bloodthorn
 * Demon
 * Demonflesh golem
 * Ironmaw
 * Living holocaust
 * Night hag
 * Nightmare
 * Varrangoin
 * Vorr
 * Vulvitor

Barrens of Doom and Despair

 * Abrian
 * Achaierai
 * Bladeling
 * Bloodthorn
 * Bonespear
 * Chronotyryn
 * Demon
 * Devil
 * Hell hound
 * Hellwasp swarm
 * Gatha
 * Haraknin
 * Ironmaw
 * Living holocaust
 * Phiuhl
 * Steel predator
 * Vaporighu
 * Varrangoin
 * Vorr
 * Vulvitor
 * Yugoloth

Blood Rift

 * Slasrath
 * Yugoloth

Clangor

 * Barghest
 * Fiendish wolf

Deep Caverns

 * Dune stalker
 * Kaorti
 * Rukarazyll
 * Vaporighu

Demonweb Pits

 * Abyssal ghoul
 * Blood fiend
 * Demon
 * Myrlochar

Fury's Heart

 * Abrian
 * Bloodthorn
 * Ironmaw
 * Khaasta
 * Phiuhl
 * Varrangoin
 * Vorr
 * Vulvitor
 * Yugoloth

Hammergrim

 * Durzagon
 * Maug

The Nine Hells

 * Bonespear
 * Devil
 * Gathra
 * Haraknin
 * Hellfire golem
 * Imp
 * Maelephant

Nishrek

 * Hellwasp swarm

Supreme Throne

 * Chaos beast
 * Demodand
 * Howler
 * Slaad