(these guys fit into any given LOTR-esque fantasy universe)

Smelter dragons, also affectionately termed such things as“lava-belchers”, “volcanobacks”, and “those damned metal thieves”, are a wingless species of dragon native to almost the entire world. The individuals that most people will ever see are fairly small, generally no longer than fifteen feet, but they have the potential to grow very large. 

The smelter dragon resembles a cross between an ankylosaurus and a bearded dragon. Thick, pillar-like legs, a fairly wide, stocky body, and an utter lack of wings make it a fairly distinctive creature. The tail is thick, broad, and powerful, edged with nodules or spines, often clubbed at the tip. The head is wide with short, blunt horns, the gold-red eyes are small and heavily shielded but surprisingly expressive, and the nostrils can shut against irritants. The body is varying shades of dark grey and brown, resembling the native stones and ores of its birthplace, but most of the back is covered in metal. 

From the back of the dragon juts several short, wide scale projections, completely hollow, spaced evenly and usually in pairs. The dragon will have four to eight of these, generally six, and rarely may have an odd number. The scales form a tube of sorts, leading down to a cavern of incredible heat inside the dragon’s body. 

The dragon will consume any metal it can find, especially harder metals, and melt the metal inside its body. Most of the metal is then spouted out the tubes, dripping down the dragon’s back and solidifying over its scales, and the dragon will tilt itself this way and that to evenly spread the metal. Smelter dragons with a regular supply of metal quickly grow to resemble turtles, very heavily protected turtles. The metal on their backs is cool, but caution should be taken around the volcano-like projections of the tubes, as the air venting from them is very hot. 

Despite their massive size, smelter dragons can burrow, and burrow well. Depending on the materials, the ground may collapse back behind them. They have thick, blunt, strong claws on their forepaws, particularly in the younger individuals, and will use these, their head, and sheer blunt force to dig. 

They stick to their own schedule, sleeping every few hours regardless of time of day. To sleep, they dig out a divot and hunker into it, burying their heads in the ground to expose only their armored backs and tails. They are difficult to wake in this state. If a sleeping smelter needs to be woken, the best bet is to either uncover the head and tap on its metal cap, or dig down to its snout and place food directly over its nostrils. They generally respond to such awakenings with bemused stares, and will often go back to sleep if not immediately offered a good reason to stay awake. 

Smelter dragons are extremely docile. They feed on minerals, ores, and the occasional dead animal, rarely chewing on plants. They seem to have a fondness for salt, either rock or sea salt, and will eagerly follow anyone offering them a large enough amount. They may wander into human settlements, where the only real danger they pose is in their accidental destruction of whatever they walk through. Their sight is not good and they tend to disregard fences. They may also bother blacksmiths by attempting to eat the metals, or enter butcher’s shops. Towns which live in an area near smelter habitat often keep salt licks on hand as lures, and befriend the local dragons. 

Smelter dragons do not speak, but seem to be intelligent. They learn quickly to recognize individual humans, and appear to understand gestures. It may be that they are sapient and simply cannot understand human languages.

Living near smelter dragons is not without benefits. They have no interest in gold, preferring harder metals, and will bring gold-rich ores in exchange for other metals if they learn that this trade is possible. They also make excellent solutions for undead infestations, as their tough armor makes them invulnerable to weaponry attacks and they possess a natural immunity to all known toxins and most curses. They simply wade into a horde of undead, crouch down, and leisurely eat any which wander in range of their mouths, ignoring any attempts at killing them. They can also be used to dispose of diseased corpses and cursed objects, and will happily eat either. 

Despite their docile nature, smelter dragons are not to be trifled with. They breathe a deep, roiling fire laced with fragments of metal when upset, their heavy bodies and thick tails enable them to destroy anything that comes within range, and their scales and adopted armor make them invulnerable to most attacks. They simply have to hunker down, hiding their bellies, and wait. If sufficiently agitated, they spout a substance similar to lava from their backs, and can spray it twice their height or more into the air and cover a large distance around them in the spray. An agitated smelter dragon is an extremely destructive force, but, fortunately, is easily calmed by removal of the problem and offers of salt, metal, and quiet words. Also fortunately, they are very difficult to upset, and generally voice their upset in deep growls, angry grunts, and gusts of hot air far before resorting to violence. 

Smelter dragons are largely nomadic unless they find an area they enjoy. If they meet a being they like, find a large vein of ore, or otherwise locate an area of easy meals, they tend to settle in. They are neutral-to-friendly towards most other creatures, and are generally willing to tolerate being climbed upon. If the situation can be explained or they can be bribed with a meal, they can even be persuaded to pull wagons, remove carts from ditches, or demolish structures. They are occasionally known to rescue creatures in distress, such as digging both animals and beings alike out of mudslides. 

Overall, the smelter dragon is a peaceful creature, not to be feared or hated and certainly not to be hunted. 

By and large, smelter dragons are small by dragon standards. They are born only about three feet long and nearly square, adorably stocky, and grow slowly over many decades until they reach usual full size at about fifteen feet long. This has led to speculation about whether they truly qualify as dragons, despite their massive potential age, immunity to most magic, evident intelligence, and inexhaustible supply of heat regardless of food intake. They also lack wings or any flight ability and inherent magical abilities beyond heat production.

It is in their ideal habitat when they reveal their truly draconic nature. Smelter dragons can only mature to their full potential when they find an unoccupied volcano which has recently erupted, or is about to erupt and is still hot. A smelter encountering a volcano will first burrow or climb inside and taste the lava, which informs it whether or not the area is occupied. 

If the area is not occupied, the dragon dives in and stays submerged, feeding on the lava to massively increase its internal heat. This allows it to melt its shell away from its back, which will eventually be replaced with compounds of metal which do not match any known metal or metal alloy. Potentially, the dragons somehow manufacture this substance. 

They also grow. Massively. It is unknown what they feed on or how long it takes them to grow, as they live deep under the surface of the ground, swimming in the magma under the earth. Eventually they reach utterly massive sizes, larger than many castles, and seem to become almost completely blind. The eyes become simple yellow orbs, the nostrils close up and are covered over in a thin layer of metal, and they trade their audible sounds for deep rumblings that shake the lava around them and are so deep that they are barely audible to humans. 

Surface smelter dragons can live easily centuries, if not more. The grown individuals, often referred to as magma dragons, are thought to live for far longer. Again, there is no way to tell, as their still-nomadic nature (they only occasionally revisit their first volcano, ignoring it entirely if it cools off) makes them impossible to observe for long and there is no known way to survive entering their home. 

The significant link to smelter dragons is what happens if a volcano near a magma dragon erupts. The eruption often spews lava especially high into the air, is accompanied by particularly loud quakes and ear-splitting, ground-shaking rumbling noises, and lasts for considerably longer than usual. It does, however, tend to angle away from nearby life. Magma dragons seem to be aware of large concentrations of living creatures, and may rupture the wall of the volcano or tunnel a new exit for the lava to direct the lava away from towns. They may not be aware of smaller towns or be able to direct the lava properly, however, so a volcano inhabited by a magma dragon is not guaranteed to be safe. 

Smelter dragons are drawn to nearby volcanic eruptions. Unless absolutely delighted by their current home, they will happily plunge into an uninhabited area of magma. More to their interest, though, is an inhabited one. When a smelter dragon meets a magma dragon, they sing to each other, deep, nearly subsonic rumbles that shake the ground and can be heard from miles away. Eventually, the smelter dragon vanishes into the lava, though keeping its shell by unknown means. It and the magma dragon will stay close together, granting an extremely rare look at a magma dragon to any who can endure the heat long enough to look into the open volcano, and the magma dragon will keep the volcano uncapped. A few days to a week later, the smelter will emerge, bringing with it anywhere from one to four eggs, and they will sing to each other once more before the magma dragon vanishes.

Smelter eggs are approximately three feet long and extremely heavy, seemingly made of solid volcanic rock, with an inner heat.The eggs are, at first, transported by being wrapped in metal and stuck to the smelter’s sides. Once the smelter finds a safe area, the eggs will be placed in a nest cavity, deep underground and floored with metals. The nest cavity will be kept extremely hot by virtue of a strange mixture of metals that stays much hotter for much longer than normal, and the walls are often coated in metals. If the walls collapse, the dragon displays no signs of alarm, simply digs its way down to the eggs again. When not out looking for food, it will typically lay on top of or next to the eggs. 

Baby smelters hatch small, loud, and extremely clumsy, and will be fed the same metal mixture as their nest until they begin to develop a shell. They stay with the parent for six months to a year, in which time they grow to about five feet long, then gradually spread out. Unless food runs low, they often stay in roughly the same area as the parent until they gain a couple more feet in length, then wander off to find their own home. 

Smelter dragons are neither social nor solitary. They tend to be found alone simply because they wander frequently, but have no objections to groups so long as there is enough food. If food runs low, one or both will leave. If they encounter each other, they rub gently against each other, rumble gently (seemingly informing each other of where food is or is not), and often sleep next to each other for an hour or so before they continue on their way. 

There are no known predators of smelter dragons, nor do they seem to have parasites. Certain organisms may attempt to steal portions of their metal shell, but are generally repelled or outright killed by a quick blast of hot air. Other dragons may chase smelters from their territory, but generally have minimal interest in them, as smelters have no interest in gold, silver, and most traditional precious metals. In fact, they often partner up with less hostile dragons to sculpt lairs, and may be found living with friendlier large dragons. Minidrakes often enjoy them and can be found perching all over them, though smelter dragons don’t seem to hear most of the high-pitched noises that minidrakes make. Essentially, smelter dragons are the capybaras of dragons.