HD 3-18+, AC as plate, 3 attacks or breath, move 90′, fly 240′, morale 9, # 1
A dragon’s age and power are reflected by hit dice. To determine dragon hit dice randomly, roll 3d6. If the result is all sixes, roll another d6, adding the result to the previous total. Continue this procedure as long as sixes are rolled.
Hit dice also determines the damage inflicted by a dragon’s fiery breath. For example, a 12 hit die dragon will do 12 dice of damage to all in the area of effect (half damage if a save is made). Once a dragon has breathed fire, they must wait 1-3 rounds before they can breath again. Breath weapon damage dice, like standard hit dice, are always d8s. The breath weapon range is equal to the number of hit dice multiplied by 10 feet, and it spreads out like a cone (the dragon has approximate control over the cone width).
Dragons may either breath fire or make up to three physical attacks (these could be bites, claws, tail slams, or any other kind of attack that makes sense in the situation at hand). Each physical attack does one die of damage. The die used should be that closest to the total number of hit dice the dragon possesses. For example, an 8 hit die dragon does d8 damage per hit. A 9 hit die dragon would do either d8 or d10 damage per hit (decide beforehand, determine randomly, or alternate).
Dragons are huge, scaled, lizard-like, fire-breathing monsters of great cunning, greed, and intelligence. Their intelligence, however, is of an alien sort. Being almost entirely self-sufficient, they have little use for society or technology, and are unable to relate (other than superficially) with lesser beings regarding these matters. They seek only treasure, ever growing domain, and occasionally worship. Unlike most creatures, age only adds to a dragon’s power. Surviving wyrmlings become ever more dangerous.
The youngest dragons are pony-sized, and generally grow until they reach the size of an elephant in body (though their length from nose to tail and wing span will be much greater). Though there seems to be no absolute limit on dragon size, the rate of their growth does slow significantly once they have reached that size. In color, their scales are inky black, earthy brown, mouldy green, rocky gray, or bloody crimson (or some combination thereof). Dragons enjoy eating any kind of meat, particularly living meat, though they do not require it for sustenance. A dragon deprived of meat for too long, however, will become surly.
Dragon reproduction is mysterious. They are thought to hatch from eggs, but have never been found in mated pairs and will rarely cooperate. They are by nature agents of chaos, and logic suggests that they would burn themselves out over time. However, this has not happened.
A dragon can be subdued by nonlethal damage. A subdued dragon will turn on their master if they perceive weakness, but will otherwise continue to serve as long as they are fed well and rewarded with treasure (a good rule of thumb would be about half of treasure accumulated). Dragons will also generally challenge their master when they have grown into another hit die, but this will sometimes take longer than their master’s lifespan. Such dragon lords often become petty tyrants, though their rule rarely lasts long due to the inherent instability of the relationship.
I think that in later versions of D&D, dragons have come to be somewhat deified. I don’t like this. I think that dragons should be fearsome and terrifying, but I don’t think you should need to be a demigod to challenge one. A young dragon should be something that could be run down by a fourth level fighter with a lance (given some luck), or even found on the first level of a dungeon.
In terms of style, there is a tension between the monstrous dragon and the sleek panther-like dragon. The sleek dragon has come to dominate fantasy art. The monstrous dragon tends to look more like it came from a fairy tale, and is often (though not always) fat. For examples, see the Holmes basic set dragon, the Rankin/Bass Smaug, the animated Flight of Dragons movie, or almost any painting of St. George and the dragon. For examples of the sleek dragon, see current D&D dragons and the work of Jeff Easley. I am interested in portraying a more mythic dragon, though still influenced by Tolkien’s Smaug. None of the gimmicky multicolored D&D chromatic dragons. My dragons all breath fire.
Regarding behavior, I want to emphasize that dragons do not live by the same rules as mortal races. I picture dragons as intelligent, but alien and prone to underestimating others.
Incidentally, I didn’t stick that bit in their about dragons not needing food for sustenance with any particular goal in mind; it just felt right given their embodiment of ever-growing power and danger. This, in concert with the growth of dragons due to increasing hit dice, might however explain why dragons sometimes get stuck underground. I’m not going to look that gift horse in the mouth. Maybe they even originate in the underworld and must reach the surface before they grow too big. Or maybe, like adventurers, they go underground in search of treasure, but sometimes outgrow their entrance.
In OD&D, total hit dice varied by dragon type, but age (and hit points per die) were determined by one d6 roll (1 being very young, 6 being very old). A similar procedure is used by the original Monster Manual, though a d8 is used instead. This is interesting, but odd. It means that given a 10 hit die dragon, there only exist dragons with hit point totals in a multiple of 10. I like the identification of age with hit dice, but rather than vary the HP per hit die (is that done with any other monster?), why not vary the number of hit dice for age? This also scales the attack bonus, which makes sense to me.
Traditionally, in both OD&D and B/X, breath weapon damage is non-random. It does automatic damage equal to the dragon’s remaining HP. I changed this because I like uncertainty, I like to roll dice, and I don’t like to expose monster health meters.
The rules for dragons take up an inordinate amount of space in pretty much all the editions I have looked at. Despite that, I still feel like my draft is a bit too wordy. Three paragraphs of rules and four of flavor. Any tips or suggestions are welcome (as always).