Huge dragon, lawful evil

Armor Class: 19

Hit Points: 225

Speed: 40 ft , fly: 80 ft , burrow: 40 ft

STR

25 +7

DEX

10 +0

CON

23 +6

INT

16 +3

WIS

15 +2

CHA

19 +4

Saving Throws: DEX +5, CON +11, WIS +7, CHA +9

Skills: Perception +12, Stealth +5

Damage Immunities: Lightning

Senses: Blindsight 60ft., Darkvision 120ft., Passive Perception 22

Languages: Common, Draconic

Challenge Rating: 16 ( 15000 XP)

Proficiency Bonus: +5

Actions

Multiattack. The dragon can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.   Bite. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 18 (2d10 + 7) piercing damage plus 5 (1d10) lightning damage.   Claw. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) slashing damage.   Tail. Melee Weapon Attack: +12 to hit, reach 15 ft., one target. Hit: 16 (2d8 + 7) bludgeoning damage.   Frightful Presence. Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 17 Wisdom saving throw or become frightened 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. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.   Lightning Breath (Recharge 5–6). The dragon exhales lightning in a 90-­foot line that is 5 feet wide. Each creature in that line must make a DC 19 Dexterity saving throw, taking 66 (12d10) lightning damage on a failed save, or half as much damage on a successful one.

Legendary Actions

The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The dragon regains spent legendary actions at the start of its turn.   Detect. The dragon makes a Wisdom (Perception) check.   Tail Attack. The dragon makes a tail attack.   Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 10 feet of the dragon must succeed on a DC 20 Dexterity saving throw or take 14 (2d6 + 7) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

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.

• 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.

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.   Blue dragons make their lairs in deserts and other arid landscapes. They prefer warm climates, but if an otherwise ideal potential lair presents itself in a cold environment, they find ways to adapt. Instead of seeking out lofty domiciles, blue dragons build their lairs underground, burrowing beneath sand or using magic to hew rock into an intricate warren of rooms and tunnels that can be expanded to accommodate a growing family. Still, they appreciate the tactical advantages of height and usually create their lairs near a spire or cliff from which they can keep watch over their territory.   Though most blue dragons would be loath to the use the term themselves, their lairs are often surprisingly homey. They favor lairs that balance beauty and comfort and adorn them in soothing shades of blue, purple, and green.   Some potential blue dragon lair features are as follows:

• The walls of the lair are crystallized glass formed by the dragon’s lightning breath. Most of its floors are loosely packed sand, with patches of rough stone showing through in some areas. The dragon has constructed a system of mirrors to bring in sunlight from chambers open to the sky, a system that not only brightly lights the interior but also heats the sand to a comfortable basking temperature.
• Entrance Chamber. An open central cavern is the lair’s primary entrance. The glass walls rise 30 feet to the surface and are fused with carved stone pillars and partial walls from the ancient city. A narrow, jagged piece of granite juts out horizontally from the wall near the top of the chamber, providing a perch from which the dragon can survey the cavern. The sand covering the floor of the chamber sometimes ripples or swirls ominously, perhaps in response to unpredictable desert winds, the dragon’s magic, or some creature lurking beneath the sand.
• Hoard Display. Just off the entrance chamber (toward the left side of the map), a smaller cavern with a worked stone floor contains the dragon’s artfully arranged hoard. The glass walls of this chamber are studded with blue gems, and narrow light wells let in sunlight that bathes the room in dappled blue light. The ancient stone tiles on the floor contain lightning-charged traps to blast intruders.
• Dragon’s Den. The dragon sleeps in a large chamber in the bottom right of the map. The den is a well-preserved remnant of the ancient city; this gracious, elegant space is hung with silk curtains in shades of blue and purple, and its worked-stone floor is covered with plush, patterned rugs in complementary hues. It features a bejeweled and cushioned dais on which the dragon often reclines.
• Private Entrance. Just above and to the right of the den is a small chamber open to the sky that the dragon uses as a private entrance to the lair. A secret door prevents unwitting creatures from wandering directly into the den.
• Treasury. At the left end of the den, a door set under a blue-tiled arch leads to a smaller room where the dragon keeps relics that are too precious for the main hoard or that don’t match the hoard’s overall aesthetic.

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.   Some possible additional regional effects are as follows:
• 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.
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 jewelry 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.

Suggested Environments

Coastal, Desert