D&D started out with a singular demon, the Balrog. Then, after a cease & desist from the Tolkien estate, that one was renamed Balor, and slightly altered to sidestep copyright laws. Then, in Eldrich Wizardy the interplanar floodgates were opened, and a whole slew of demons were added to the game, which among with even more options were included in the original Monster Manual.
Ever since its original incarnation, there has been a moteley crew of Demons and Daemons (later "Yogoloths") in the D&D Monster Manual. Of course, demons are evil chaos incarnate, and there should be endless variations of unique demons, not just a few known, standard types. But combinatorial Monster creation was ony done for Hordlings in the MM, and never caught on - more work, less recognizable. So what we have are the standard demon types, originally with the most boring names one could think of: Demon Type I, II, III etc. In the Monster Manual, they were then given made-up names in parentheses, which became the standard names for these demons (even though they only were supposed the type name type I-III, and only an example of a name for type IV-VI).
Finally, in the BECMI 1985 Immortals set, these same types were given pretty cool, evokative names, which unfortunately never made it into the mainstream names. So ever since, we have been using the parenthetical, made-up names for these demons.
- Type I = "Screaming Demon" (a.k.a. "Air Demon", "Winged Fury")
- Type II = "Croaking Demon" (a.k.a. "Swamp Demon", "Gobbler")
- Type III = "Howling Demon" (a.k.a. "Fire Demon", "Four Armed Horror")
- Type IV = "Groaning Demon" (a.k.a. "Forest Demon", "Biter")
- Type V = "Hissing Demon" (a.k.a. "Water Demon", "Destroyer")
- Type VI = "Roaring Demon" (a.k.a. "Mountain Demon", "Manslayer")
- Succubus = "Whispering Demon" (a.k.a. "Charmer", "Grey Deceiver")
In later works, demons were grouped into those Type classes, based on how dangerous they were. As I like the idea of evokative, descriptive names. So I made up some more for some of the others in italics, for use in my games.
Demon | CR | Class | Descriptive Name | Looks | Origin |
Rutterkin | 2 | Minor | Warped | Stiltskin-like | MMII |
Abyssal Wretch | 1/4 | Minor | Wretched | | MMII |
Quasit | 1 | Minor | Plotting | Imp-like | |
Maw Demon | 1 | Minor | Maw | Critters-like | |
Dretch | 1/4 | Minor | Snarling | Pug-like | |
Manes | 1/8 | Sub, Minor | Whining | Undead-like | Ancient Rome |
Vrock | 6 | Type I | Srceaming / Screeching | Vulture-like | Gygax, S3:EW |
Barlgura | 5 | Type I, (old: Minor) | Ululating | Ape-like | Lewis Spence's Encycopedia |
Shadow Demon | 4 | Type I | Shadow | Shadow-like | FF |
Babau | 4 | Type I (old: Minor) | Stalking | Skeleton-like | Mediterranean Folklore |
Dybbuk | 4 | | | Jellifish-like | Jewish Myth, FC:HotA |
Bulezau | 3 | | Bleeting | Goat-like | MC:Planescape Appendix II |
Hezrou | 8 | Type II | Croaking | Toad-like | Gygax, S3:EW |
Armanite | 7 | | | Centraur-like | FCI:HotA |
Maurezhi | 7 | | | Ghoul-like | MC:Planescape Appendix |
Chasme | 6 | Type II, minor | Buzzing | Fly-like | MMII |
Glabrezu | 9 | Type III | Howling | Dog-like | Gygax, S3:EW |
Yochlol | 10 | Type III | Handmaiden of Lolth | Roper-like | Gygax, ItdotE |
Alkilith | 11 | | Door | Opening-like | MC:Planescape Appendix |
Nalfeshnee | 13 | Type IV | Groaning / Grunting | Boar-like | Gygax, S3:EW |
Wastrilith | 13 | | Corrupting | Serpent-like | MC:Outer Planes Appendix |
Marilith | 16 | Type V | Hissing | Snake-like | Hindu Myth |
Nabassu | 15 | Major | Souleater | Bat-like | Mesopotamian Myth |
Balor | 19 | Type VI | Roaring | Balrog-like | Tolkien |
Goristro | 17 | Type VI | Bellowing | Bull-like | FCI:HotA |
Sibirex | 18 | | | Wolf-like | FCI:HotA |
Molydeus | 21 | | Bile | Bodyhorror-like | FCI:HotA |
| | | | | |
Partial Demon | | | | | |
Succubus | 4 | | Whispering | Seductress-like | S3:EW, Judean Myth; later also Incubus, now Shapechanger, not demon |
Cambion | 5 | Human female+demon | | | |
Alu-Demon | [5] | Human male+Succubus | | | Akkadian/Sumerian Myth, MMII |
Draegloth | 7 | | Half Drow/Demon | Werewolf-like | |
| | | | | |
| | | New Name | | |
Charonadaemon | 3 | | Merrenoloth | Charon-like | MMII |
Mezzodaemon | 5 | | Mezzloth | Beetle-like | FF |
Derghodaemon | 7 | | Dergholoth | Insect-like | MMII |
Canodaemon | 8 | | Canoloth | Dog-like | MC:Planescape Appendix |
Hydrodaemon | 9 | | Hydroloth | Frog-like | MMII |
Nycaldaeomon | 9 | | Nycaloth | Demon-like | FF |
Piscodaemon | | | | Crawfish-like | MMII |
Yagnodaemon | 11 | | Yagnoloth | Hellboy-like | MMII |
Oinodaemon | 12 | | Oinoloth | Ram-like | MMII, originally Antrhaxus |
Arcanadaemon | 12 | | Arcanaloth | Fox-like | MMII |
Ultrodaemon | 13 | | Utroloth | Alien-like | MMII |
| | | | Bear-like (varies) | FF |
| | | | | |
Demodands | | | | | |
Farastu | | | Tarry | | MMII |
Kelubar | | | Slime | | MMII |
Shator | | | Shaggy | | MMII |
| | | | | |
Slaadi | | | | | |
Red Slaad | 5 | | | | FF |
Blue Slaad | 7 | | | | FF |
Green Slaad | 8 | | | | FF |
Grey Slaad | 9 | | Executioners | | FF |
Death Slaad | 10 | | Lesser Masters | | FF |
Demon Possession & Binding
Another issue with the D&D demons is that they are for the most part just boring bashers, especially in 5e. Many of them even cannot teleport, so they work like dressed-up, powerful ogres that smash you, maybe with some spell ability thrown in. That does not fit at all to all the wonderful themes of demonic influence and corruption and possession. Compare this to Elric!, where there is a rich narrative field enabled by evil demons bound into weapons and items, that give their wielder power but also work to corrupt them. Or look at the biblical stories, where a whole horde of demons possed one man, and were driven out.
Normally, this kind of stuff in D&D is just story dressing, DM-fiat background, with no rules to support it at all. How could such rules sensibly look like, without being to powerful in the hands of the players.
Demonic Items
For demonic magic items, I think one can largely re-use the rules for sentinent items (p. 214, 5e DMG 20214). The alignment of the item will be the demon's, as will be the Int, Wis and Cha scores, instead of rolling them randomly. The normal rules for domination or shutting off of powers apply.
Creating the item. You need to prepare the item to receive the demon, using the normal crafting cost and rules. Then you use this item in place of a diamond worth 1,000 gp, as your component for Planar Binding, to bind the demon into the item after you summoned it and held it captive, either forcing the demon in, or striking a deal with it. In either case, there must be a purpose for the item and demon, which, when fulfilled, will free the demon. (I guess Stormbringers objective was to undo the multiverse and become all powerful.) You probably only should be able to create a demonic item from binding
Powers: An item with a bound demon is in any case magical and thus deals magical damage. The cost and rarity of the item further should be commesurate with the powers that the demon gives to the item. The powers should be in line with the powers of the demon. They could include the item having the demon's perception or sharing some special perception with the wielder, giving the wielder a damage resistance, dealing special extra damage, or allowing the wielder to cast one or more of the spells the demon can cast, without components, at the demon's rate of casting.
Attunement: In most cases, narratively it would make sense to require such an item to need attunement. Use this as the default, and use the normal criteria to figure out if the item needs attunement to see if you can leave it off.
For example, if you bound a Glabrezu Demon into a longsword. This demonic longsword would deal magical damage, could communicate telephatically with the wielder, and allow the wielder to have the sword cast fly once per day (without needing their own concentration). With attunement, this could be an uncommon with attunement. (A normal magical +1 weapon does not need attunement, which is a big difference, and it increases your damage and to hit; plus flight here is more limited compared to both broom and wings of flying which need attunement). A rare onyx fly needs no attunement, even though it lasts 12 hours and gives you a full creature, although you cannot use it every day; at rare, it might be OK to have this have no attunement, especially because the corrupting influence of the demon and its agenda adds a real downside to the item. Truesight, which the demon also has, or unlimited dispel magic per day both seem way too powerful. Truesight is an 8th level spell, and the only item granting it on a persistent basis is the Eye of Vecna. And unlimited castings of third level spells are nothing characters get, even at 20th level. Maybe you could allow this at higher rarities for detect magic.
Another example, an helmet in the shape of a vulture, with a Vrock bound into it, that grants darkvision and poison resistance to the wearer, and once per day can emit a Stunning Screech (as per the Vrock) ability. This probably should require attunement, and be very rare. Compare to rod of rulership which is rare and likewise can turn one battle around in a material way, and ring of resistance which is also rare, and this combines both.
Demonic Possession
For this, one could give all the greater demons (or groups of lesser demons) the Possession ability from the Ghost. The DC should probably be based on the CR of the Demon. If the Ghost at CR 5 has a DC of 13, and the characters get increases to their PB increase every four levels if they are proficient in the save so their saves increase (plus if you improve Cha with your stat increase, that gets better too), maybe +1 for every 3 CRs added or taken. DC 14 at CR 8, DC 15 at CR 11, DC 16 at CR 14, and DC 17 at CR 17 and DC 18 at CR 20. For comparison, the Balor (CR 19) death throes has DC 20, so this is below that benchmark.
For hordes of smaller demons, one could sum up their combined CR, if they all use their action to enter. The demon classes are unfortunately all over the place, not reasonably based on CR bracktes. Minor demons range from CR 5 for a Barlgura all the way down to CR 1/4 for a Dretch. But one could say, as long as their combined CR is not at least 5, they cannot posses.
For example, if a group of Dretches (CR 1/4) tries to possess someone , you need 4 of them for CR 1, and so you need 20 of them for CR5. That is 20 of them not multi-attacking and not belching a fetid cloud to force a possession save, which is a big opportunity cost. With 20, you'd expect at least one critical hit for 16 damage, no matter what ACs. Once you get the 20, they can try, and then would all together enter the host.