Adult Blue Dragon

Blue dragons, also known as storm dragons, were orderly creatures and are unusual for chromatics in that they keep fairly well-ordered, hierarchical societies. They were more likely to be mocking and manipulative than outrightly cruel or murderous to 'lesser' creatures, aided greatly by their natural talents for hallucination. They were infamous for tricking desert travelers into drinking sand or going miles out of their way to avoid nonexistent dust basins. Their breath weapon was a line of lightning or a large electrical discharge.
Vain and territorial, blue dragons soar through the skies over deserts, preying on caravans and plundering herds and settlements in the verdant lands beyond the desert's reach. These dragons can also be found in dry steppes, searing badlands, and rocky coasts. They guard their territories against all potential competitors, especially brass dragons.
A blue dragon is recognized by its dramatic frilled ears and the massive ridged horn atop its blunt head. Rows of spikes extend back from its nostrils to line its brow, and cluster on its jutting lower jaw.
A blue dragon's scales vary in color from an iridescent azure to a deep indigo, polished to a glossy finish by the desert sands. As the dragon ages, its scales become thicker and harder, and its hide hums and crackles with static electricity. These effects intensify when the dragon is angry or about to attack, giving off an odor of ozone and dusty air.
Vain and Deadly. A blue dragon will not stand for any remark or insinuation that it is weak or inferior, taking great pleasure in lording its power over humanoids and other lesser creatures.
A blue dragon is a patient and methodical combatant. When fighting on its own terms, it turns combat into an extended affair of hours or even days, attacking from a distance with volleys of lightning, then flying well out of harm's reach as it waits to attack again.
Desert Predators. Though they sometimes eat cacti and other desert plants to sate their great hunger, blue dragons are carnivores. They prefer to dine on herd animals, cooking those creatures with their lightning breath before gorging themselves. Their dining habits make blue dragons an enormous threat to desert caravans and nomadic tribes, which become convenient collections of food and treasure to a dragon's eye.
When it hunts, a blue dragon buries itself in the desert sand so that only the horn on its nose pokes above the surface, appearing to be an outcropping of stone. When prey draws near, the dragon rises up, sand pouring from its wings like an avalanche as it attacks.
Overlords and Minions. Blue dragons covet valuable and talented creatures whose service reinforces their sense of superiority. Bards, sages, artists, wizards, and assassins can become valuable agents for a blue dragon, which rewards loyal service handsomely.
A blue dragon keeps its lair secret and well protected, and even its most trusted servants are rarely allowed within. It encourages ankhegs, giant scorpions, and other creatures of the desert to dwell near its lair for additional security. Older blue dragons sometimes attract air elementals and other creatures to serve them.
Hoarders of Gems. Though blue dragons collect anything that looks valuable, they are especially fond of gems. Considering blue to be the most noble and beautiful of colors, they covet sapphires, favoring jewelery and magic items adorned with those gems.
A blue dragon buries its most valuable treasures deep in the sand, while scattering a few less valuable trinkets in plainer sight over hidden sinkholes to punish and eliminate would-be thieves.

A Blue Dragon's Lair

Blue dragons make their lairs in barren places, using their lightning breath and their burrowing ability to carve out crystallized caverns and tunnels beneath the sands.
Thunderstorms rage around a legendary blue dragon's lair, and narrow tubes lined with glassy sand ventilate the lair, all the while avoiding the deadly sinkholes that are the dragon's first line of defense.
A blue dragon will collapse the caverns that make up its lair if that lair is invaded. The dragon then burrows out, leaving its attackers to be crushed and suffocated. When it returns later, it collects its possessions-along with the wealth of the dead intruders.

Chromatic Dragons

The black, blue, green, red, and white dragons represent the evil side of dragonkind. Aggressive, gluttonous, and vain, chromatic dragons are dark sages and powerful tyrants feared by all creatures-including each other.
Driven by Greed. Chromatic dragons lust after treasure, and this greed colors their every scheme and plot. They believe that the world's wealth belongs to them by right, and a chromatic dragon seizes that wealth without regard for the humanoids and other creatures that have "stolen" it. With its piles of coins, gleaming gems, and magic items, a dragon's hoard is the stuff of legend. However, chromatic dragons have no interest in commerce, amassing wealth for no other reason than to have it.
Creatures of Ego. Chromatic dragons are united by their sense of superiority, believing themselves the most powerful and worthy of all mortal creatures. When they interact with other creatures, it is only to further their own interests. They believe in their innate right to rule, and this belief is the cornerstone of every chromatic dragon's personality and worldview. Trying to humble a chromatic dragon is like trying to convince the wind to stop blowing. To these creatures, humanoids are animals, fit to serve as prey or beasts of burden, and wholly unworthy of respect.
Dangerous Lairs. A dragon's lair serves as the seat of its power and a vault for its treasure. With its innate toughness and tolerance for severe environmental effects, a dragon selects or builds a lair not for shelter but for defense, favoring multiple entrances and exits, and security for its hoard.
Most chromatic dragon lairs are hidden in dangerous and remote locations to prevent all but the most audacious mortals from reaching them. A black dragon might lair in the heart of a vast swamp, while a red dragon might claim the caldera of an active volcano. In addition to the natural defenses of their lairs, powerful chromatic dragons use magical guardians, traps, and subservient creatures to protect their treasures.
Queen of Evil Dragons. Tiamat the Dragon Queen is the chief deity of evil dragonkind. She dwells on Avernus, the first layer of the Nine Hells. As a lesser god, Tiamat has the power to grant spells to her worshipers, though she is loath to share her power. She epitomizes the avarice of evil dragons, believing that the multiverse and all its treasures will one day be hers and hers alone.
Tiamat is a gigantic dragon whose five heads reflect the forms of the chromatic dragons that worship her-black, blue, green, red, and white. She is a terror on the battlefield, capable of annihilating whole armies with her five breath weapons, her formidable spellcasting, and her fearsome claws.
Tiamat's most hated enemy is Bahamut the Platinum Dragon, with whom she shares control of the faith of dragonkind. She also holds a special enmity for Asmodeus, who long ago stripped her of the rule of Avernus and who continues to curb the Dragon Queen's power.

Dragons

True dragons are winged reptiles of ancient lineage and fearsome power. They are known and feared for their predatory cunning and greed, with the oldest dragons accounted as some of the most powerful creatures in the world. Dragons are also magical creatures whose innate power fuels their dreaded breath weapons and other preternatural abilities.
Many creatures, including wyverns and dragon turtles, have draconic blood. However, true dragons fall into the two broad categories of chromatic and metallic dragons. The black, blue, green, red, and white dragons are selfish, evil, and feared by all. The brass, bronze, copper, gold, and silver dragons are noble, good, and highly respected by the wise.
Though their goals and ideals vary tremendously, all true dragons covet wealth, hoarding mounds of coins and gathering gems, jewels, and magic items. Dragons with large hoards are loath to leave them for long, venturing out of their lairs only to patrol or feed.
True dragons pass through four distinct stages of life, from lowly wyrmlings to ancient dragons, which can live for over a thousand years. In that time, their might can become unrivaled and their hoards can grow beyond price.

Dragon Age Categories

Category	Size	Age Range
Wyrmling	Medium	5 years or less
Young Dragon	Large	6–100 years
Adult Dragon	Huge	101–800 years
Ancient Dragon	Gargantuan	801 years or more
Greatwyrm	Gargantuan	1,200 years or more

Lair Actions

On initiative count 20 (losing initiative ties), the dragon takes a lair action to cause one of the following effects; the dragon can't use the same effect two rounds in a row:
Part of the ceiling collapses above one creature that the dragon can see within 120 feet of it. The creature must succeed on a DC 15 Dexterity saving throw or take 10 (3d6) bludgeoning damage and be knocked prone and buried. The buried target is restrained and unable to breathe or stand up. A creature can take an action to make a DC 10 Strength check, ending the buried state on a success.
A cloud of sand swirls about in a 20-foot-radius sphere centered on a point the dragon can see within 120 feet of it. The cloud spreads around corners. Each creature in the cloud must succeed on a DC 15 Constitution saving throw or be blinded for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Lightning arcs, forming a 5-foot-wide line between two of the lair's solid surfaces that the dragon can see. They must be within 120 feet of the dragon and 120 feet of each other. Each creature in that line must succeed on a DC 15 Dexterity saving throw or take 10 (3d6) lightning damage.

Additional Lair Actions.

At your discretion, a legendary (adult or ancient) blue dragon can use one or both of the following additional lair actions while in its lair:
Misleading Mirage. Until initiative count 20 on the next round, at each intersection or branching passage in the lair, a creature other than the dragon has a 50 percent chance of going in a different direction from the direction it intends.
Sudden Sinkhole. The dragon chooses a point on the ground that it can see within 120 feet of it. A 5-foot-radius, 20-foot-deep pit forms centered on that point. A creature on the ground above where the pit formed must make a DC 15 Dexterity saving throw. On a failed save, a creature falls to the bottom of the pit, taking 7 (2d6) bludgeoning damage and landing prone. On a successful save, a creature moves to the nearest unoccupied space instead of falling in the pit.

Regional Effects

The region containing a legendary blue dragon's lair is warped by the dragon's magic, which creates one or more of the following effects:

• Thunderstorms rage within 6 miles of the lair.
• Dust devils scour the land within 6 miles of the lair. A dust devil has the statistics of an air elemental, but it can't fly, has a speed of 50 feet, and has an Intelligence and Charisma of 1 (-5).
• Hidden sinkholes form in and around the dragon's lair. A sinkhole can be spotted from a safe distance with a successful DC 20 Wisdom (Perception) check. Otherwise, the first creature to step on the thin crust covering the sinkhole must succeed on a DC 15 Dexterity saving throw or fall 1d6 × 10 feet into the sinkhole.
• If the dragon dies, the dust devils disappear immediately, and the thunderstorms abate within 1d10 days. Any sinkholes remain where they are.

Additional Regional Effects.

Any of these effects might appear in the area around a blue dragon's lair, in addition to or instead of the effects described in the Monster Manual: Blue Luster. Creatures that spend a year within 1 mile of the dragon's lair find blue objects fascinating and feel compelled to acquire them at every opportunity.
Mirage Terrain. The area immediately surrounding the lair appears to be a lush oasis. A creature carefully examining the illusion can attempt a DC 15 Intelligence (Investigation) check to disbelieve it. A creature who disbelieves the illusion sees it as a vague image superimposed on the underlying terrain.
Sandstorm. A sandstorm blows constantly within 1 mile of the dragon's lair.
This is an article about Adult Blue Dragons, but there is a main page with more general info on Blue Dragons and there may be ones for the other age ranges in the future.

Lifespan

101-800 years, then considered an Ancient Dragon

Average Height

13' -15'

Average Weight

1,000 - 1,500 lbs.

Average Length

28' - 30'