# Dragon

DDDDDDDDDD dragon 

Difficulty

20

Attacks

Breath (see article), bite 3d8, claw 1d4, claw 1d4

DDDDDDDDDD dragon 

Difficulty

20

Attacks

Breath (see article), bite 3d8, claw 1d4, claw 1d4

Base level

15

Base experience

460

Speed

9

Base AC

-1

Base MR

20

Alignment

-7 (blue)
-6 (black)
-5 (white)
-4 (red)
4 (gray, silver)
5 (orange)
6 (green)
7 (yellow)

Frequency (by normal means)

1 (Very rare)

Genocidable

Yes

Weight

4500

Nutritional value

1500

Size

Gigantic

Resistances

(see article)

Resistances conveyed

(see article)

A dragon:

 can fly.

 has no hands.

 has a thick hide.
 can lay eggs.

 can see invisible creatures.

 is carnivorous.

 is normally generated hostile.

 is nasty.
 is strong.

 likes gold.
 likes gems.

 can pick up magical items.

A red dragon also:

 can be seen through infravision.

A green dragon also:

 is poisonous to eat.

A yellow dragon also:

 is acidic to eat.

Reference

monst.c#line1161

The dragon, represented by the overall glyph D, is a class of very powerful mid-game monster in NetHack. Dragons are coveted for the dragon scales they sometimes drop, which can be made into dragon scale mail.
Members of the dragon monster class include:

D&nbsp;gray dragon
D&nbsp;silver dragon
D&nbsp;red dragon
D&nbsp;white dragon
D&nbsp;orange dragon
D&nbsp;black dragon
D&nbsp;blue dragon
D&nbsp;green dragon
D&nbsp;yellow dragon
Baby dragons
D&nbsp;baby gray dragon
D&nbsp;baby silver dragon
D&nbsp;baby red dragon
D&nbsp;baby white dragon
D&nbsp;baby orange dragon
D&nbsp;baby black dragon
D&nbsp;baby blue dragon
D&nbsp;baby green dragon
D&nbsp;baby yellow dragon
Unique monsters
D&nbsp;Chromatic Dragon
D&nbsp;Ixoth

The following information pertains to an upcoming version (NetHack 3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

Gold (and baby gold) dragons are added. They emit light and breathe fire. Main details should go on Gold dragon.
Deferred monsters in the dragon class are:

D&nbsp;shimmering dragon
D&nbsp;baby shimmering dragon
Contents

1 Common characteristics

1.1 Adult dragons
1.2 Baby dragons
1.3 Death drops
1.4 Generation
1.5 Quest nemeses

2 Elemental affinities
3 Deferred dragons
4 Baby dragons
5 Strategy

5.1 Combat
5.2 As pets
5.3 Intrinsics and food sources

6 Origin
7 History
8 Variants

8.1 UnNetHack
8.2 SLASH'EM
8.3 SlashTHEM
8.4 Biodiversity patch
8.5 FIQHack
8.6 SpliceHack
8.7 EvilHack

9 Encyclopedia entry
10 References

Common characteristics
All dragons are carnivorous monsters that are thick-skinned, capable of flight, and are eligible steeds. They are generally slower than an unburdened, unhasted hero. Dragons generated randomly and at level creation will always be hostile, and are eligible polyforms for polymorph traps and other sources of polymorph.
Dragons are intelligent and can pick up gold and gems, but lack defined hands (the default tiles depict them as quadrupedal), and thus cannot use any items they come across or happen to be carrying, e.g. after transformation via polymorph trap.

Adult dragons
All adult dragons are either lawful or chaotic, with an AC of -1 and an MR of 20. They are strong, gigantic, oviparous, can see invisible, and have the M2_NASTY flag; an associated bit of code in trap.c allows them to instantly tear through webs where their baby forms cannot.[1] All adult dragons possess a breath weapon of an element corresponding to their color. In addition to gold and gems, dragons will pick up magical items such as wands and scrolls, but the aforementioned lack of hands and their inability to speak prevents them from using any of their spoils.

Baby dragons
All baby dragons are of neutral alignment, with an AC of 2 and an MR of 10. They are strong and huge, but lack the adult dragon's ability to use breath weapons, tear through webs, and see invisible. Baby dragons can grow up into their adult forms, which causes their scales to grow in (hence the AC difference of 3 between their forms).

Death drops
Dragons will always leave a corpse if killed in a way that leaves it intact, and adults have a 1 in 3 chance of also dropping a set of their uncursed +0 scales (1 in 20 if the dragon was revived); baby dragons do not drop scales, nor do their corpses grant intrinsics. Adult dragon corpses that grant intrinsics are guaranteed to do so.

Generation
Baby dragons, like all baby monsters, are randomly generated only on levels that are eligible for baby monsters, e.g., aligned branches like the neutral-biased Oracle and Sokoban levels. Thus they are usually excluded from monster generation on level creation that calls for a D unless it specifically generates a baby dragon. Baby dragons can also be hatched from dragon eggs.
Adult dragons are first eligible to be generated through normal random monster creation around the midway depths of the dungeon. They are also considered throne room monsters, and can be generated in throne rooms on level creation or when a throne is looted as early as dungeon level 15.[2] Adult dragons are all eligible for creation via the summon nasties monster spell when cast by a spellcaster of the same alignment.
Where most monsters roll (ML)d8 for their HP - with ML being the monster's level - an adult dragon instead rolls (ML)d4 and adds 4 times its monster level to that result, e.g., a level 15 dragon will always have at least 75 HP. Dragons generated in the End Game use a flat 8*(ML), and so will always have the maximum amount of HP possible for their level (e.g., the level 15 dragon from before would always have 120 HP if generated there).[3]
In addition to random generation, adult dragons are generated on level creation for the following areas:

Four dragons are generated around the moat of Fort Ludios, with one random dragon placed at each cardinal direction.
Many dragons appear on the Healer quest - five random dragons are generated for the home, locate and goal levels, and four random dragons are generated in the filler levels between them.
Four dragons are guaranteed to appear in the Castle, with two random dragons occupying each of the alcoves between the storerooms.
Three random dragons will be generated upon reaching the Astral Plane.
Quest nemeses
Two dragons serve as quest nemeses in the game: the D&nbsp;Chromatic Dragon, the Caveman quest nemesis, and D&nbsp;Ixoth, the Knight quest nemesis. Neither of them leave behind any scales upon death. 
Ixoth is a powerful red dragon and thus possesses the standard fire breath alongside many other abilities - eating him conveys fire resistance.
The Chromatic Dragon is a special kind of dragon - she possesses the breath weapon of every single dragon in the game, and eating her corpse conveys a random resistance from the ones availble via adult dragon meat. Her corpse is poisonous to eat, however.

Elemental affinities
Each adult dragon has a specific element-and-resistance set of characteristic associated with it, including a breath attack. Eating a given dragon's corpse can give you the associated intrinsics if possible, while the scales (and any mail made from them) will grant the extrinsic characteristic.

Dragon

Breath (4d6 unless otherwise noted)

Intrinsics/scales

Corpse conveys...

Black

disintegration

disintegration resistance

same (100%)

Blue

lightning

shock resistance

same (100%)

Gray

magic missile

magic resistance

nothing (magic resistance cannot be gained intrinsically)

Green

poison

poison resistance

same (100%)

Orange

sleep, 4d25 turns

sleep resistance

same  (100%)

Red

fire 6d6

fire resistance

same (100%)

Silver

cold

reflection and cold resistance; only reflection is provided by scales

nothing (reflection cannot be gained intrinsically)

White

cold

cold resistance

same (100%)

Yellow

acid

acid resistance and petrification resistance; only acid resistance is provided by scales

nothing (neither resistance can be gained intrinsically)

Deferred dragons
The shimmering dragon, whose scales grant displacement, appears in the code along with its baby form, but is commented out by default - monster displacement has not yet been implemented in vanilla NetHack. However, variants make used of them, such as SLASH'EM.

The following information pertains to an upcoming version (3.7.0). If this version is now released, please verify that it is still accurate, then update the page to incorporate this information.

Displacer beasts have been successfully added to the latest in-development version, indicating that monster displacement is now possible.
Baby dragons

DDDDDDDDDD baby dragon 

Difficulty

13

Attacks

Bite 2d6

DDDDDDDDDD baby dragon 

Difficulty

13

Attacks

Bite 2d6

Base level

12

Base experience

200

Speed

9

Base AC

2

Base MR

10

Alignment

0 (neutral)

Frequency (by normal means)

0 (Not randomly generated)

Genocidable

Yes

Weight

1500

Nutritional value

500

Size

Huge

Resistances

(see article)

Resistances conveyed

None

A baby dragon:

 can fly.

 has no hands.

 has a thick hide.

 is carnivorous.

 is normally generated hostile.

 is strong.

 likes gold.
 likes gems.

A baby red dragon also:

 can be seen through infravision.

A baby green dragon also:

 is poisonous to eat.

A baby yellow dragon also:

 is acidic to eat.

Reference

monst.c#line1085

Baby dragons generally possess the resistances of their adult forms. However, baby silver dragons do not possess reflection, which is provided by the adult's scales.[4] They grant no intrinsics when eaten, they do not drop scales, and they do not have breath attacks. 

Strategy
While baby dragons may not be especially difficult due to being held back by their lesser defenses and only having a single bite attack, adult dragons are somewhat fearsome foes - the value of their scales and the frequency at which they start appearing from the midgame on make them threats that every player must eventually prepare for.

Combat
Dragons will use their breath weapons only at range (i.e., more than one square from the character) - players that get within melee distance can avoid the breath attacks, but will have to contend with their powerful bite and subsequent claw attacks. Characters without magic cancellation, magic resistance, or reflection to avoid or negate the breath's rays may prefer this option, and good AC is almost a must in any case.
Dragons are considered kebabable, granting a +2 to-hit bonus when attacking them with weapons that use the spear skill. In addition, Dragonbane deals double damage to all dragons, and the reflection it grants when wielded is perfect for dealing with their breath attacks - thus it is especially useful when farming for scales. Those looking to make dragon scale mail may opt to use a cursed scroll of genocide to generate dragons of their desired color, which is best done in conjunction with an engraved Elbereth or scroll of scare monster; it is wisest to attempt this in a smaller room to reduce the chances of breath attacks occurring.

As pets
Dragons are excellent pets in the early game if you obtain one. The easiest way to get a dragon pet is through a dragon egg; the egg may be obtained by polymorphing into any of the dragons and then sitting if your character is female. If you repeatedly displace your pet onto a polymorph trap you will occasionally end up with a gray dragon, since they are magic-resistant and will not polymorph further.
The most recommendable colors for adult dragons are silver and gray, as both are immune to death rays; silver dragons are also immune to disintegration breath, while gray ones are immune to polymorph traps. Yellow is a good option too, due to stoning resistance.
Pet dragons can be used as steeds with the advantages of flight, fighting strength, and preference for meaty corpses, which makes them easy to feed. However, their lack of speed ensures they will spend most of their time either catching up with you or eating said corpses; even after making them fast (e.g., by zapping a wand of speed monster at them), their movement speed still pales in comparison to many other available steeds, though the flight and breath weapon may still make them a worthwhile choice. Players making use of dragon pets or steeds may want to carry a magic whistle.
While baby dragons lack scales and intrinsic resistances, one can still use tame baby dragons to obtain scales and/or resistances. Pet baby dragons will eventually grow up into their adult forms, which can then be killed (possibly via conflict or by rendering them non-tame through abuse) for their scales and intrinsics.
Obtaining pet baby dragons can be accomplished via controlled polymorph for a female character fairly easily: all dragons are oviparous, and baby dragons coming from laid eggs will be tame. A male character can use an amulet of change to swap genders - if one is not available, he can also repeatedly polymorph into a dragon using the spell or the ring until he changes sex. This has a 10% chance to occur with each polymorph.[5][6]

Intrinsics and food sources
Dragon corpses are very high-nutrition and filling, and eating after being satiated abuses your wisdom if you are lawful. Using a tinning kit is preferred if you plan to chew through several servings of dragon in a short time. Most dragons are also among the relatively few monsters in NetHack that are guaranteed to confer an intrinsic, so they are also worth tinning as backup sources of those intrinsics in case they are lost (e.g., to a gremlin attack at night).

Origin

Wikipedia has an article about:
Dragon 

The dragon is a large, serpentine, legendary creature that appears in the folklore of many cultures worldwide. Beliefs about dragons and dragon-like beings vary considerably through regions, but dragons in European cultures since the High Middle Ages have often been depicted as winged, horned, four-legged, and capable of breathing fire. Dragons and similar creatures in various Asiatic cultures - such as the Chinese lung (traditional 龍, simplified 龙, Japanese simplified 竜, Pinyin lóng) associated with good fortune and thought to have power over rain - are usually depicted as wingless, four-legged, serpentine creatures with above-average intelligence; they are also typically more benevolent compared to the European dragon, and many East Asian deities and demigods have such creatures as their personal mounts or companions. Other common traits of dragons often include: snakelike features, reptilian scaly skin, four legs with three or four toes on each, spinal nodes running down the back, a tail, and a serrated jaw with rows of teeth. 
The earliest attested reports of draconic creatures occur in the mythologies of the ancient Near East, particularly in ancient Mesopotamian art and literature; stories about storm-gods slaying giant serpents occur throughout nearly all Indo-European and Near Eastern mythologies, such as that of Marduk and Tiamat. Other famous prototypical draconic creatures include the Leviathan in the Hebrew Bible; the Grand'Goule in the Poitou region of France; and Python, Wyvern, and the Lernaean Hydra in Greek mythology. Variants such as SLASH'EM and UnNetHack along with some patches have made use of these and other names for draconian creatures, as explored in detail below.
The Western dragon's image is based on a conflation of earlier dragons and giant serpents from different traditions, mixed with inaccurate scribal drawings of snakes; according to several modern scholars, huge extinct or migrating crocodiles bear that lived in forested or swampy areas were likely a template for modern dragon imagery. These dragons are generally depicted as cave-dwellers and treasure-hoarders with ravenous appetites, and are a frequent fixture of Western fantasy literature where they are portrayed as monsters to be tamed or overcome by saints or culture heroes, such as J. R. R. Tolkien's The Hobbit and the popular legend of Saint George and the Dragon.

History
Hack 1.0 has the standard dragon, which does not have an explicit color. This early dragon breathes fire and its corpse confers fire resistance, making it equivalent to the modern red dragon. A dead dragon is the only way to get intrinsic fire resistance in Hack, so it was quite likely that the player wouldn't have acquired it yet by the time they would see one. This, combined with the ability to use their breath attack in melee on top of their normal melee attacks, made them significantly more dangerous; furthermore, reflection would not be introduced until much later. Such would remain true for thee earlier versions of NetHack.
NetHack 2.3e introduces all of the modern dragon types and their associated breath weapons, except for silver. The corpse is still referred to as a "dead dragon" regardless of type, and eating it always confers fire resistance. Black dragon breath causes instadeath, and there is no reflection, disintegration resistance, or amulet of life saving, making genocide tempting - but fire resistance is necessary to traverse Hell, and there is no method of genociding only black dragons.
NetHack 3.0.0 introduces baby dragons, distinguishes the dragons and their corpses by type, and also introduces dragon scale mail; in this series, dragon scale mail is obtained by polymorphing a dragon corpse. Reflection is introduced in this version, and black dragon breath is toned down a bit. The changes to how dragons are distinguished also makes it possible to genocide only black dragons.
NetHack 3.1.0 introduces dragon scales as a death drop and the current method of obtaining dragon scale mail. This version also adds the Quests, and with them the Chromatic Dragon and Ixoth. Hell is replaced by Gehennom in this version, and fire resistance is no longer necessary to enter (though it is still heavily recommended).
NetHack 3.3.0 adds the silver dragon along with its corresponding baby form and scales from 3.1.3 variant SLASH 6.

Variants
Variants of NetHack often subject dragons to extensive changes, as well as adding new monsters to the class. The deferred shimmering dragon is one such frequent addition.

UnNetHack
Dragons have been substantially modified in UnNetHack. All dragons have been given new names and have their breaths, resistances, and colors randomized - with the exception of chromatic dragons, which possess the resistances and breath weapons of all dragons. As a result, it is impossible to predict breath type based on name or color.
This randomization happens at the start of the game, but all dragons of the same name or color within a game are of the same type - dragons are auto-identified upon witnessing their breath attack, and identifying one dragon also identifies all dragons of that type. In addition, a new type of breath attack has been added - lava breath that does heavy fire damage and melts walls instead of bouncing. 
Glowing dragon scales and scale mail function as an infinite light source, in addition to providing the resistance that glowing dragons possess in that individual game. Chromatic dragon scales and scale mail provide all dragons' resistances, including reflection.
The following are the names given to random dragons in UnNetHack:

leviathan
tatzelworm
lindworm
guivre
sarkany
amphitere
wyvern
draken
sirrush
glowing dragon
SLASH'EM
Main article: Dragon (SLASH'EM)
SLASH'EM adds two new colored dragons: the formerly deferred shimmering dragon D and the deep dragon D, whose scales give displacement and drain resistance, respectively. The hydra and wyvern are two other new additions to the monster class, and SLASH'EM dragons in general undergo a few additional changes that distinguish them from the dragons of NetHack.

SlashTHEM
SlashTHEM adds two new colored dragons: the golden dragon D and the stone dragon D, whose scales give sickness resistance and petrification resistance respectively. Additionally, SlashTHEM adds a new unique dragon called the Dragon Lord located in The Wyrm Caves, who drops the artifact Scales of the Dragon Lord on death.

Biodiversity patch
The biodiversity patch renames the vanilla dragons (minus the gray dragon) in a manner similar to UnNetHack, but does not randomize their traits.

FIQHack
FIQHack dragons are significantly faster (speed 20 instead of 9), and their claw attacks are 1d8 instead of 1d4. In addition, they have special AI that allows them to use their breath weapon in melee range, and they will try to move more intelligently in general: they will keep you in their line of fire when possible, or move out of that line when they can't use their breath, and will flee to preserve survival.
FIQHack also includes the deferred shimmering dragons from vanilla, which have innate displacement and stunning breath, and whose scales confer displacement when worn.
Dragon breaths operate as skilled ray-type wands: there is a chance per breath attack that it will bypass reflection.  Disintegration breath never does this.

SpliceHack
Main article: Dragon (SpliceHack)
SpliceHack adds several new dragon flavours and new dragon special abilities. Older dragons gain increasingly powerful breath weapons.

EvilHack
EvilHack dragons have been significantly enhanced – they spawn with much more hit points (especially in the End Game), can engulf and digest creatures smaller than them, and their scales each have some form of a secondary passive attack (which is passed on to the scales and any mail made out of them).

Encyclopedia entry

In the West the dragon was the natural enemy of man.  Although preferring to live in bleak and desolate regions, whenever it was seen among men it left in its wake a trail of destruction and disease.  Yet any attempt to slay this beast was a perilous undertaking.  For the dragon's assailant had to contend not only with clouds of sulphurous fumes pouring from its fire breathing nostrils, but also with the thrashings of its tail, the most deadly part of its serpent-like body.

[ Mythical Beasts by Deirdre Headon (The Leprechaun Library) ]

"One whom the dragons will speak with," he said, "that is a dragonlord, or at least that is the center of the matter.  It's not a trick of mastering the dragons, as most people think. Dragons have no masters.  The question is always the same, with a dragon:  will he talk to you or will he eat you?  If you can count upon his doing the former, and not doing the latter, why then you're a dragonlord."

[ The Tombs of Atuan, by Ursula K. Le Guin ]

 

References

↑ trap.c in NetHack 3.6.6, line 2543: extra_nasty() discerns adult dragons from baby dragons to let them tear through webs

↑ courtmon in mkroom.c

↑ src/makemon.c in NetHack 3.6.6, line 969

↑ muse.c in NetHack 3.6.6, line 2156

↑ polyself.c in NetHack 3.6.6, line 292

↑ polyself.c in NetHack 3.6.6, line 467