Hordlings (also spelled Hordelings) are a species of anarchic lesser fiends from the multiverse of Dungeons & Dragons. These small, highly mutable fiends are native to Hades in the Great Wheel, and to the Abyss in the World Axis. Both versions are the lowliest form of fiend, but they have certain unique traits.
Great Wheel Hordlings
In the Great Wheel, hordlings are what happens when larvae - the petitioner form of evil souls - are allowed to fester for too long, resulting in each wicked soul being reborn as a uniquely deformed fiend. As their name implies, these ragtag fiendlings gather in huge hordes, roaming aimlessly across Hades and the other Lower Planes and picking fights with anything they encounter. Some believe that they are the ultimately foundational forms of all fiendish races, and that if left alone long enough, a hordling might grow up into a proper fiend, but this is basically nonsense.
Now, hordlings were never a popular creature for one single reason: an ultra-mutable fiendish mook may sound like fun on paper, but when you have to roll to generate the traits yourself - the 2e entry consists of twelve tables just to determine combat abilities, and then another seven for aesthetic traits - it becomes a lot less fun. Add in that hordlings are supposed to come in huge hordes and... yeah, they grow tiresome to generate pretty damn quickly.
See for yourself: http://www.mojobob.com/roleplay/monstrousmanual/h/hordling.php
Hordlings first appeared in the Monster Manual II for Advanced Dungeons & Dragons 1st edition. They then received an update to 2e in the Outer Planes Appendix for the Monstrous Compendium, and were subsequently reprinted in the Planescape MCA. They made the jump to 3rd edition in issue #124 of Dungeon Magazine, which tried to make their mutability less imposing by making it mostly aesthetics, and dividing them up into several distinct types; the dread gnasher, the skullreaver, the spittlemaw, the vulturewretch, and the advanced hordling.
World Axis Hordelings
In the World Axis, hordelings embody the unholy fecundity of the Abyss; they are literally scraps of elemental corruption and chunks of demon flesh born from the seething tides of profane energy emanating from that plane. When demons slaughter each other in battle, the corpses become the seed of new generations; the raw elemental substances of demonic carcasses is impregnated with the essence of pure evil that permeates the Abyss, causing new tiny fiendlings to rise up and carry on with the circle of birth, pain and death that keeps the Abyss alive.
Hordelings do have some overlap with manes, in that they are the very least form of demon in the World Axis, generated spontaneously from the Abyss and potentially growing and evolving into stronger demons - either morphing into an established breed, or potentially becoming their own breed. However, most hordelings are typically lobbed across battlefields, crushed underfoot, consumed or slaughtered willy-nilly in demon games before they get much of a chance to experience living.
The 4e hordeling was detailed in the splatbook "The Book of Vile Darkness", where it came in the form of the Hordeling Mob (level 11 Elite Brute Swarm) and the Hordeling Breakaway (level 11 Minion Brute). An article in issue #197 of Dungeon Magazine, "Creature Incarnations: Hordelings" restored the idea of the Greater Hordeling, an exceptional or long-lived hordeling that is on the verge of maturing into a "real" demon.
|The inhabitants of the Planes of Planescape|
|Upper Planes:||Aasimon - Angels - Animal Lords - Archons - Asuras - Eladrin - Guardinals - Lillend|
|Middle Planes:||Formians - Githzerai - Inevitables - Marut - Modrons - Rilmani - Slaadi|
|Lower Planes:|| Alu-Fiends - Baatezu - Bladelings - Cambions - Demodands - Erinyes - Hags |
Hordlings - Imps - Kytons - Marilith - Obyrith - Succubi - Tanar'ri - Yugoloth
|Transitive Planes:||Astral Dreadnought - Githyanki|
|Inner Planes:||Azers - Elementals - Genies - Grues - Mephit - Salamanders - Sylphs|
|Sigil:||Dabus - Cranium Rats|
|High-ups:||Archangels - Archdevils - Archfey - Archomentals - Demon Princes|