Lunar dragons (also known as moon dragons or phase dragons) are capricious, xenophobic creatures that make their lairs inside desolate moons by burrowing through the rock.
Before laying eggs, a female lunar dragon stocks her lair with food; she won’t leave the lair again until the eggs hatch and the offspring are old enough to fend for themselves. Lunar dragon eggs have stony shells that are pale white to light gray in color. Lunar dragons are alabaster white when they hatch and gradually turn darker as they age. Ancient moon dragons are the color of slate.
Lunar dragons enjoy depriving other creatures of treasure more than acquiring the treasure themselves. Often found among the treasures in a lunar dragon’s hoard are one or more spelljamming helms taken from vessels that dared to invade the dragon’s territory.
A lunar dragon can become incorporeal, but not to the extent that it can pass through other creatures or solid objects. In this semi-incorporeal state, roughly half of the dragon’s body has a dark, indistinctly spectral form.
Gargantuan Dragon, Typically Neutral Evil
Armor Class: 18 (natural armor)
Proficiency Bonus: +6
Hit Points: 297 (17d20 + 119)
Speed: 40 ft., burrow 20 ft., fly 80 ft.
STR – 27 (+8)
DEX – 12 (+1)
CON – 24 (+7)
INT – 12 (+1)
WIS – 15 (+2)
CHA – 17 (+3)
Saving Throws: Con +13, Wis +8
Skills: Perception +14, Stealth +13 Damage Immunities cold
Senses: darkvision 240 ft., passive Perception 24
Challenge: 19 (22,000 XP)
Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.
Tunneler. The dragon can burrow through solid rock at half its burrowing speed and leaves a 20-foot-diameter tunnel in its wake.
Unusual Nature. The dragon doesn’t require air.
Multiattack. The dragon makes one Bite attack and two Claw attacks.
Bite. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 15 (2d6 + 8) piercing damage plus 7 (2d6) cold damage.
Claw. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 15 (2d6 + 8) slashing damage.
Tail. Melee Weapon Attack: +14 to hit, reach 20 ft., one target. Hit: 15 (2d6 + 8) bludgeoning damage.
Cold Breath (Recharge 5–6). The dragon exhales a blast of frost in a 90-foot cone. Each creature in the cone must make a DC 21 Constitution saving throw. On a failed save, the creature takes 36 (8d8) cold damage, and its speed is reduced to 0 until the end of its next turn. On a successful save, the creature takes half as much damage, and its speed isn’t reduced.
Phase (3/Day). The dragon becomes partially incorporeal for as long as it maintains concentration on the effect (as if concentrating on a spell). While partially incorporeal, the dragon has resistance to bludgeoning, piercing, and slashing damage.
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.
Tail Attack. The dragon makes one Tail attack.
Treacherous Ice. Magical ice covers the ground in a 20-foot radius centered on a point the dragon can see within 120 feet of itself. The ice, which is difficult terrain for all creatures except lunar dragons, lasts for 10 minutes or until the dragon uses this legendary action again.
Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 21 Dexterity saving throw or take 12 (1d8 + 8) bludgeoning damage and be knocked prone. The dragon can then fly up to half its speed without provoking opportunity attacks.
A Lunar Dragon’s Lair
The cave complex where a lunar dragon makes its lair contains ample space for food, as well as one or more hidden chambers where the dragon keeps its treasure. Depending on the composition and features of the moon, the lair might contain natural springs and heat vents, wild gardens, crystal formations, magical phenomena, or an ecosystem of lesser life forms that have adapted to living with the dragon.
The region containing an ancient or adult lunar dragon’s lair is warped by the dragon’s magic, which produces one or more of the following effects:
Black Frost. A thin layer of black frost covers the ground, which kills all ordinary plants growing within 6 miles of the lair if the dragon is ancient, or within 3 miles if the dragon is an adult.
Haunting Moan. A haunting sound gets louder or fainter (dragon’s choice) the closer one gets to the lair. The moan is audible 6 miles from the lair if the dragon is ancient, or 3 miles if the dragon is an adult.
Moon Devils. Swirling funnels of dust and frost known as moon devils crisscross the area within 1 mile of the lair, intercepting other creatures they encounter. A moon devil is a free-willed air elemental that deals cold damage instead of bludgeoning damage.
If the dragon dies, the moaning stops, the moon devils dissipate, and the black frost disappears over the course of 1d10 days, allowing plant life in the area to recover.