“I desired dragons with a profound desire. Of course, I in my timid body did not wish to have them in the neighborhood. But the world that contained even the imagination of Fáfnir was richer and more beautiful, at whatever the cost of peril.”
The current season of Game of Thrones has led to a significant amount of speculation about dragons - are they in fact the nuclear weapons of fantasy warfare, would they actually let us ride them and use us for war, etc. These are not uninteresting questions - although it may say a great deal about us as a society that when confronted by a creature of such ancientry, malice, and peril, that we immediately begin to speculate on how we might best use them to murder our fellows (however hypothetical).
However, I want to sidestep the discussion of Game of Thrones (which, for one thing, I do not watch), and look at dragons as a Medievalist and Germanic Philologist. This might be of interest to those who like to dig around the roots of things, or to those sub-creating fantasy worlds of their own who would like their ideas of dragons to be more rooted in primary world myths and legends.
I'm particularly interested in the serpents, dragons, wyrms, and other assorted reptilian monstrosities belonging to Indo-European mythology. There's a very rich tradition of these things in Chinese/Japanese folklore, of course, but they are separate things, and I do not want to give those traditions short shrift by lumping them in with my own particular area of study. For our purposes, Indo-European dragons include everything from Vritra, the drought-dragon Indra killed, to Python, the earth dragon-serpent Apollo slew, to Fafnir, the archetypal wyrm of Germanic legend, to the dragon of Eden which St. George slew. What are these dragons like, and what do they do?
The prototypical dragon is a very large serpent. Sometimes they are given legs, and sometimes wings, but the shape of a dragon seems to be serpentine enough that the language used to describe them is chiefly words which can be equally applied to serpents. So Sanskrit ahi, Old English wyrm, etc. Over time as various regional versions of these stories came into contact with each other, a sort of taxonomy of dragons arose, but we should be careful not to enforce our Monster Manual sensibilities backwards onto the Middle Ages. A linnormr and a wyvern are just two names describing the same winged, bipedal serpent. By tradition dragons are very fierce and hard to kill, but also very parochial, as a rule choosing a hill, forest, sacred stream, barrow, or mountain as their primary dwelling place, from which to dominate the land around them. This makes them ill-suited to employment as a sort of pet airforce.
To understand whey they do these things, and also why and how they are killed (and by whom) we need to understand a little more about dragon's motivations. To do that I want to look at three examples which I think are particularly good dragons: Vritra, Fafnir, and Beowulf's Bane (who may be named Starkheart).
Vritra is a dragon, or a demon in the form of a dragon, who in the Rig Veda takes all of the waters of all the rivers in the world and hoards them under a mountain. This is of course disastrous for the world - no fresh water and no fertile river valleys means that the ancient agrarian societies of the Indian sub-continent would completely collapse. Vritra is slain by the hero Indra, who slew him with the thunderbolt crafted for him by the god Tvashtri. This is of course on some level an iteration of the popular myth of a storm-god who slays a drought-causing monster and brings rain back to the earth (see Baal, may also be echoed in Thor slaying the Midgard Serpent). But I want to focus less on mythographical theory and more on the actual activity of the dragon: Vritra is taking something which is essential for the continuation of civilization, in this case the fresh water (and thus the fertile river valleys) needed for the agrarian society, and hoarding it in such a way that society can no longer exist. It's up to the hero, then, to kill the monster so that civilization can grow and flourish. We see echoes of similar myths in Cadmus and Apollo.
Fafnir is, as Tolkien says, the archetypal Norse dragon. What is probably often forgotten about him is that he was not always a dragon. Fafnir, in fact, was the dwarf, the son of a powerful sorcerer. After the family came into the possession of a hoard of (cursed) gold, Fafnir drove his brother off and turned into a dragon to guard the hoard himself. Along comes Sigurd the Volsung (or Sigemund in the earlier versions of the tale) who slays the dragon, with a little help. The manner of Fafnir's death is significant: Fafnir's underside is particularly vulnerable, so Sigurd/Sigemund waits in a trench dug in the path the dragon uses to slither down to a stream, and stabs him as he passes overhead. In some versions of the story, Fafnir and Sigurd have a conversation as the dragon lays dying, in which Fafnir curses Sigurd. There are two elements worth observing here: the first is that Fafnir is not merely monstrous; he is malicious. The malice of the dragon is something which we see first introduced here, but which would become an important element of the monster from this point forward. The second is the importance of the treasure hoard not as merely something which the hero gets to carry away as a sort of prize, but the whole basis for becoming a dragon in the first place. Here we see an echo of the water-hoarding of the Indra, Cadmus, and Apollo myths - gold is at least as important in the economy of Iron Age Germania as fresh water is to agrarian societies - but we see something more, too. The old name for this kind of sin is avarice. It's distinguished from greed (mere acquisitiveness) because dragons, of course, don't want to do anything with their treasure. As C.S. Lewis notes, this probably goes back to Greco-Roman myth (in Aesop's Fables, the dragon is a mere allegory for avarice), but in Fafnir the concept takes on a whole new massive, poison-belching dimension.
I mentioned just now that gold was as important as fresh water to the economy of the Iron Age Germanic peoples, the people who lived and moved in the world described by the Beowulf poem. But it wasn't merely the existence of gold (and other treasures) - it was the free flow of those things from a king or chieftain to his retainers. In that sense it's a gift-based economy. There's a significant difference (one could argue it's only semantics, but I think there's more to it than that) between the attitude of "I should serve my lord because he's always given me good gifts" (which is Wiglaf's argument in Beowulf), and "I should do what my lord says because he pays me." But of course the problem with giving gold and land and horses and other gifts is that if you aren't also on the receiving end, you start running out - and when the gifts dry up, your society falls apart. Typically this necessitates some sort of raiding of your neighbors, making this gift-based economy also a pirate economy. But consider in this context what a giant hoard of gold lying in the ground actually represents: it's not a lottery waiting to be won; that hoarded wealth represents the death of a society.
So in the Beowulf poem. We're given some backstory for the dragon's hoard (and possibly the dragon himself) in the so-called Lay of the Last Survivor:
The barrow all-ready
occupied the plain near the water-waves,
new on the headland, made secure by difficult-craft;
there inside bore of the treasure of earls
a hoard of rings a hand-fashioned share
of plated gold; some words he spoke:
'Now hold you, Earth, now the heroes cannot
earls' possessions. Listen, it formerly from you
was obtained by good men; war-death has taken away,
terrible murder of life, of crimes each one,
my belovèd people, they gave this up to me:
they had seen joy in the hall; he I have not, who might wield sword
or make beautiful this gilded flagon,
this precious drinking vessel; the veteran warriors are ill elsewhere;
must the stern helmet adorned with gold
stripped of its ornaments; the burnishers slumbers,
they who war-masks ought to brighten;
also so the army's coats of mail, which in battle endured
over the shattering of shield-boards the bite of iron,
decays along with the men; byrnie's ring may not
with war-fighter fare widely,
alongside heroes; there was not harp's joy,
delight of glee-wood, nor good hawk
soaring through the hall, nor swift horse
trampling the courtyard; baleful death has
many of my living kin sent forth.'
Thus sad at heart in grief he bemoaned
one after all, unhappily passed
days and nights, until the flood of Death
reached to his heart.
(Translation by Dr. Benjamin Slade)
Essentially, a warrior or a king, who is the last survivor of his people, takes all the wealth of his people and buries it in the earth. He either goes off to die or (and there is cause for ambiguity in the text) becomes the dragon which then guards the hoard. The dragon's subsequent outrage over the absence of a missing cup, which brings him into inevitable and fatal conflict with Beowulf, is not because he'd intended on using the cup for anything. It's outrage over being parted from even one very small portion of this hoard, which could be the foundation of a tribe or a civilization were it in circulation, but which the dragon intends to keep for himself. In fact, the cup is taken specifically to pay a weregeld (to settle a feud), which is one of the most important uses of gold in Iron Age Germania.
The dragon is of course slain. That dragons can and should be slain is one of the chief elements of all dragon stories within the Indo-European tradition. But no dragon is easy to slay. Typically you must be a hero (like Sigemund/Sigurd or Beowulf), in possession of a magical weapon (like the sword Gram, or Wiglaf's sword of significant lineage), and usually you need help (both Sigemund and Beowulf are aided by a valiant younger kinsman).
The dragon's poison is ultimately the bane of Beowulf, but Beowulf is able to stab the dragon in the belly with a seax or knife. Someone has made the comment that dragons must not have very good armor if they can be killed by a septuagenarian with a knife, but we must not forget that the septuagenarian in question is Beowulf, who even in his old age was no ordinary man, and that he manages to stab the dragon in the belly (where, let us not forget, drakes are notoriously weak), only after repeated attempts to strike its head had shattered the hero's sword.
With the dragon dead, the dying Beowulf asks Wiglaf to bring up some of the treasure from the hoard so that Beowulf can see it and go to his reward knowing that he has provided for his people; the vast treasure of the hoard ought to provide for the Geats for years to come. But when Beowulf is buried, all of the hoard is buried with him under the earth, and remains eldum swá unnyt swá hyt aérer wæs - "as useless to men as it ever was."
One of the many puzzling questions proposed by the end of the Beowulf poem is why exactly the Geats do this. One simple explanation seems to be that the hoard was regarded (as most dragon's hoards are) as cursed, and decided that was drama they didn't need. In any case, it's no use hauling off a major hoard of treasure unless you're prepared to defend it, and Beowulf was the last of the great Geatish heroes.
There is much more that could be said here, and even now I feel I have vastly oversimplified a really interesting subject. To sum up: Dragons in Indo-European myth tend to be: Serpentine, solitary, avaricious, cunning, extremely deadly (in most cases spewing poison or fire or both), and are the archetypal enemies of civilization, embodying the antithesis of whatever civilization looks like to the culture in question. For prospective world-builders, I think some very interesting takes on dragons could be done by using this basic blueprint and asking what it would look like to a culture that values something (say children) more than gold. When we start thinking about dragons as merely engines of war or tools in the no-holds-barred game of realpolitik, I think we've lost something.