Dragons are the iconic monsters of the D&D game. It could be said that as dragons go, so goes D&D. So, let's take a look at dragons from each AD&D, AD&D 2nd Edition and D&D 3rd Edition (3.5 version) and see how the game has changed in relation to these iconic beasts. And as long as we are talking about icons, we'll be looking at the most iconic dragons of the: the great red wyrms.
In AD&D
The huge, ancient red dragon in AD&D has 11 HD, 88 hp, an AC of -1, a THAC0 of 10, 3 attacks doing 1-8/1-8/3-30, firey breath that can be used 3 times per day and does the dragon's current hit points in damage, and the possibility (40%) of being able to use magic spells. It has no special resistance to magic (but saves as a 22nd level character) and can be hit by normal weapons. It's fear aura affects only up to 5 HD creatures or characters.
In AD&D 2nd Edition
The great wyrm red dragon of 2nd edition has 23 HD, 102 hp (average), an AC of -11, a THAC0 of 1, 3 basic attacks that do 1-10+12/1-10+12/3-30+12, 5 optional attacks types, firey breath that can be used once every 3 rounds and does 24d10+12 (144 average), and the ability to cast up to 5th level magic user spells and 2nd level priest spells as a 24th level caster. The dragon's innate spell resistance is 65% and it makes saving throws as a 23 HD creature. It is immune to normal missile attacks. It has some fire based spell like abilities, as well, and its fear aura can potentially affect any creature up to 22nd level/HD with a -4 penalty to the saving throw.
In D&D 3rd Edition
The 3rd edition great wyrm red dragon has 40 HD, 660 hp, an AC of 41, an attack bonus of +49 and a total of 8 potential attacks (as with the 2nd edition dragon) with the primary 3 attacks doing 4d6+8/4d6+8/4d8+17 (not counting the potential for power attack), firey breath that can be used every 1d4 rounds and does 24d10 (132 average) damage. It casts spells as a 19th level sorcerer with access to some cleric spells and has a Spell Resistance of 32 and Damage Reduction of 20/magic (making it essentially immune to normal weapons). It's fear aura can potentially affect creatures of up to 39 HD, though creatures of 5 HD or more suffer a relatively minor effect. Like the 2e dragon, it has a small selection of spell like abilities that are geared toward out of combat activities.
Looking At the Numbers
It is hard to directly compare the dragons, because they don't exist in a vaccum – the rules regarding characters changed between editions as well. This fact makes the 1st Edition to 2nd Edition leap the most notable, because there was a relatively insignificant change in character effectiveness/power between those two editions while there was an enormous power increase in the dragon. The 1E dragon was a foe suitable for mid level adventurers, a pit stop on the way to fight demons and liches. By contrast, the 2E dragon is a challenge suitable for much higher level characters – even a high level fighter with magic weapons will not be guaranteed to hit the 2E dragon every swing. Neither 1E nor 2E have a system for identifying which level of characters a particular monster is supposed to challenge.
The 3E dragon is built around the 3E characters and the Challenge Rating system of 3E. by the book, the Great Wyrm Red Dragon is intended to be a moderate challenge for 26th level characters and a difficult encounter for 22nd level characters (and is not recommended for characters under 20th level at all – though one would suspect the dragon was in fact used against lower level parties). While it has an extremely high number of hit points compared to the dragons of previous editions, 3E PCs also have a much higher damage potential (especially once level-appropriate magic items are factored in), and while it does more damage than its 2E counterpart (significantly more if things like Power Attack are factored in) 3E PCs have more hit points than their 2E versions, especially at higher levels (since 2E PCs stopped getting hit dice and con bonuses to hit points at 9th level).
What it Means
The 1E to 2E power increase, relative to player characters, of dragons indicates that the intent was to move the dragon to the upper end of the threat spectrum, to make it more than a stepping stone on the way to the more powerful creatures of the outer planes. Given the dragon's iconic position in the game, and fantasy in general, it seems a worthy goal. The shift to 3E is a little more difficult to parcel out, given that so many benchmarks by which we could measure character and/or monster effectiveness changed as well, but if one compares the great wyrm red dragon's Challenge Rating to that of other creatures in the Monster Manual, we find it at the top of the heap, with even the very powerful evil outsiders – Pit Fiends and Balors – well behind it. If anything, then, it appears as though the 3E dragon was built to maintain the place made for it in 2E or to even increase its standing among the gravest threats the PCs can face.
In AD&D
The huge, ancient red dragon in AD&D has 11 HD, 88 hp, an AC of -1, a THAC0 of 10, 3 attacks doing 1-8/1-8/3-30, firey breath that can be used 3 times per day and does the dragon's current hit points in damage, and the possibility (40%) of being able to use magic spells. It has no special resistance to magic (but saves as a 22nd level character) and can be hit by normal weapons. It's fear aura affects only up to 5 HD creatures or characters.
In AD&D 2nd Edition
The great wyrm red dragon of 2nd edition has 23 HD, 102 hp (average), an AC of -11, a THAC0 of 1, 3 basic attacks that do 1-10+12/1-10+12/3-30+12, 5 optional attacks types, firey breath that can be used once every 3 rounds and does 24d10+12 (144 average), and the ability to cast up to 5th level magic user spells and 2nd level priest spells as a 24th level caster. The dragon's innate spell resistance is 65% and it makes saving throws as a 23 HD creature. It is immune to normal missile attacks. It has some fire based spell like abilities, as well, and its fear aura can potentially affect any creature up to 22nd level/HD with a -4 penalty to the saving throw.
In D&D 3rd Edition
The 3rd edition great wyrm red dragon has 40 HD, 660 hp, an AC of 41, an attack bonus of +49 and a total of 8 potential attacks (as with the 2nd edition dragon) with the primary 3 attacks doing 4d6+8/4d6+8/4d8+17 (not counting the potential for power attack), firey breath that can be used every 1d4 rounds and does 24d10 (132 average) damage. It casts spells as a 19th level sorcerer with access to some cleric spells and has a Spell Resistance of 32 and Damage Reduction of 20/magic (making it essentially immune to normal weapons). It's fear aura can potentially affect creatures of up to 39 HD, though creatures of 5 HD or more suffer a relatively minor effect. Like the 2e dragon, it has a small selection of spell like abilities that are geared toward out of combat activities.
Looking At the Numbers
It is hard to directly compare the dragons, because they don't exist in a vaccum – the rules regarding characters changed between editions as well. This fact makes the 1st Edition to 2nd Edition leap the most notable, because there was a relatively insignificant change in character effectiveness/power between those two editions while there was an enormous power increase in the dragon. The 1E dragon was a foe suitable for mid level adventurers, a pit stop on the way to fight demons and liches. By contrast, the 2E dragon is a challenge suitable for much higher level characters – even a high level fighter with magic weapons will not be guaranteed to hit the 2E dragon every swing. Neither 1E nor 2E have a system for identifying which level of characters a particular monster is supposed to challenge.
The 3E dragon is built around the 3E characters and the Challenge Rating system of 3E. by the book, the Great Wyrm Red Dragon is intended to be a moderate challenge for 26th level characters and a difficult encounter for 22nd level characters (and is not recommended for characters under 20th level at all – though one would suspect the dragon was in fact used against lower level parties). While it has an extremely high number of hit points compared to the dragons of previous editions, 3E PCs also have a much higher damage potential (especially once level-appropriate magic items are factored in), and while it does more damage than its 2E counterpart (significantly more if things like Power Attack are factored in) 3E PCs have more hit points than their 2E versions, especially at higher levels (since 2E PCs stopped getting hit dice and con bonuses to hit points at 9th level).
What it Means
The 1E to 2E power increase, relative to player characters, of dragons indicates that the intent was to move the dragon to the upper end of the threat spectrum, to make it more than a stepping stone on the way to the more powerful creatures of the outer planes. Given the dragon's iconic position in the game, and fantasy in general, it seems a worthy goal. The shift to 3E is a little more difficult to parcel out, given that so many benchmarks by which we could measure character and/or monster effectiveness changed as well, but if one compares the great wyrm red dragon's Challenge Rating to that of other creatures in the Monster Manual, we find it at the top of the heap, with even the very powerful evil outsiders – Pit Fiends and Balors – well behind it. If anything, then, it appears as though the 3E dragon was built to maintain the place made for it in 2E or to even increase its standing among the gravest threats the PCs can face.