Dragon, Cave - Adult

Covered in black spikes, the dragon’s eyeless head swings from side to side. Darkness creeps from its strange, eel-like hide, spreading like ink in water.

Apex predators of the underworld, cave dragons are the stuff of nightmare for creatures with little else to fear. They can speak, but they value silence, speaking rarely except when bargaining for food.

Born to Darkness. Eyeless, these dragons have long, thin spikes that help them navigate tunnels, or seal passages around them, preventing foes from outflanking them. Their stunted wings are little more than feelers, useful in rushing down tunnels. Their narrow snouts poke into tight passages which their tongues scour free of bats and vermin. Young cave dragons and wyrmlings can fly, poorly, but older specimens lose the gift of flight entirely.

Cave dragon coloration darkens with age, but it always provides good camouflage against stone: white like limestone, yellow, muddy brown, then black at adult and older categories. Mature adult and old cave dragons sometimes fade to gray again.

Ravenous Marauders. Cave dragons are always hungry and ready to eat absolutely everything. They devour undead, plant creatures, or anything organic. When feeding, they treat all nearby creatures as both a threat and the next course. What alliances they do make only last so long as their allies make themselves scarce when the dragon feeds. They can be bribed with food as easily as with gold, but other attempts at diplomacy typically end in failure. Cave dragons do form alliances with derro or drow, joining them in battle against the darakhul, but there is always a price to be paid in flesh, bone, and marrow. Wise allies keep a cave dragon well fed.

A Hard Life. Limited food underground makes truly ancient cave dragons almost unheard of. The eldest die of starvation after stripping their territory bare of prey. A few climb to the surface to feed, but their sensitivity to sunlight, earthbound movement, and lack of sight leave them at a terrible disadvantage.

A Cave Dragon’s Lair

Labyrinthine systems of tunnels, caverns, and chasms make up the world of cave dragons. They claim miles of cave networks as their own. Depending on the depth of their domain, some consider the surface world their territory as well, though they visit only to eliminate potential rivals.

Large vertical chimneys, just big enough to contain the beasts, make preferred ambush sites for young cave dragons. Their ruff spikes hold them in position until prey passes beneath.

Due to the scarcity of food in their subterranean world, a cave dragon’s hoard may consist largely of food sources: colonies of bats, enormous beetles, carcasses in various states of decay, a cavern infested with shriekers, and whatever else the dragon doesn’t immediately devour.

Cave dragons are especially fond of bones and items with strong taste or smell. Vast collections of bones, teeth, ivory, and the shells of huge insects litter their lairs, sorted or arranged like artful ossuaries.

Cave dragons have no permanent society. They gather occasionally to mate and to protect their eggs at certain spawning grounds. Large vertical chimneys are popular nesting sites. There, the oldest cave dragons also retreat to die in peace. Stories claim that enormous treasures are heaped up in these ledges, abysses, and other inaccessible locations.

Lair Actions

On initiative count 20 (losing initiative ties), the dragon takes a lair action for one of the following effects; the dragon can’t use the same effect two rounds in a row:

  • The ceiling collapses above one creature that the dragon can see within 120 feet of it. The creature takes 10 (3d6) bludgeoning damage and is knocked prone and restrained (by fallen debris); damage is halved and the creature is not restrained if it makes a successful DC 15 Dexterity saving throw. The creature is freed when it or an adjacent ally uses an action to make a successful DC 15 Strength (Athletics) check.
  • A ten foot-wide, ten foot-long crack opens in the cavern floor where the dragon wishes. Any creature occupying that space must make a successful DC 15 Dexterity saving throw or fall 20 feet, taking 7 (2d6) bludgeoning damage plus 7 (3d4) piercing damage from the jagged stones at the bottom.
  • The dragon summons a swarm of insects as if it had cast insect plague, filling a 20-foot radius sphere within 90 feet of the dragon. Creatures that are in the affected space or that enter it take 22 (4d10) piercing damage, or half damage with a successful DC 18 Constitution saving throw. The swarm lasts until initiative count 20 on the next round.

Regional Effects

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

  • Poisonous and odorless gases suddenly fill passages and caverns, and just as quickly disperse, within six miles of the dragon’s lair.
  • Flash flooding turns tunnels into death traps as tremors create fissures in the stone within six miles of the lair. On the surface, ponds drain away, and long-dry creek beds break their banks in flood.
  • Swarms of vermin within one mile of the lair increase in both size and number as they try to escape the dragon’s endless and undiscriminating hunger.

If the dragon dies, these effects fade over the course of 1d10 days.

Adult Cave Dragon

Huge dragon, neutral evil
Armor Class 18 (natural armor)
Hit Points 243 (18d12 + 126)
Speed 40 ft., climb 40 ft., Earth Glide
26 (+8) 12 (+1) 24 (+7) 12 (+1) 12 (+1) 20 (+5)

Saving Throws Dex +6, Con +12, Wis +6, Cha +10
Skills Perception +10
Damage Immunities acid, poison, thunder
Condition Immunities poisoned
Senses blindsight 120 ft., passive Perception 20
Languages Common, Darakhul, Draconic, Dwarvish, Goblin
Challenge 16 (15,000 XP)

Darkness Aura. An adult or older cave dragon can generate an aura of darkness that fills its space and the surrounding 20 feet. This darkness prevents normal vision and darkvision from functioning. Blindsight and truesight function normally. Activating or deactivating the aura is a bonus action.

Earth Glide. An adult cave dragon glides through stone, dirt, or any sort of earth except metal as easily as a fish glides through water. Its burrowing produces no ripple or other sign of its presence and leaves no tunnel or hole unless the dragon chooses to do so; in that case, it creates a passageway 15 feet wide by 10 feet high. The spell move earth cast on an area containing an earth-gliding cave dragon flings the dragon back 30 feet and stuns the creature for one round unless it succeeds on a Constitution saving throw.

Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.

Innate Spellcasting. The dragon’s innate spellcasting ability is Charisma (spell save DC 18). It can innately cast the following spells, requiring no material components:

At will: detect magic, speak with dead
3/day each: blur, counterspell, darkness, web
1/day each: dispel magic, hold person


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: +13 to hit, reach 15 ft., one target. Hit: 18 (3d6 + 8) piercing damage plus 3 (1d6) poison damage.

Claw. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 15 (2d6 + 8) slashing damage.

Tail. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 17 (2d8 + 8) 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 18 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.

Poison Breath (Recharge 5-6). The dragon exhales a cone of black poison gas in a 60-foot cone. Each target in that area takes 56 (16d6) poison damage and is poisoned if it is a creature; a successful DC 18 Constitution saving throw reduces damage by half and negates the poisoned condition. The poisoned condition lasts until the target takes a long or short rest or it’s removed with lesser restoration or comparable magic.


Ruff Spikes. When a creature tries to enter a space adjacent to a cave dragon, the dragon flares its many feelers and spikes. The creature cannot enter a space adjacent to the dragon unless it makes a successful DC 18 Dexterity saving throw. If the saving throw fails, the creature can keep moving but only into spaces that aren’t within 5 feet of the dragon and takes 10 (3d6) piercing damage from spikes.

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.

Reset Ruff Spikes. The dragon can use its ruff spikes as a reaction again before its next turn.

Tail. The dragon makes a tail attack.

Swift Bite (Costs 2 Actions). The dragon makes two bite attacks.

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