Prismatic Dragon, Ancient

Family: Dragons

Gargantuan dragon, neutral

Armor Class 20 (natural armor)
Hit Points 407 (22d20 + 176)
Speed 50 ft., climb 40 ft.

25 (+7) 10 (+0) 27 (+8) 20 (+5) 17 (+3) 19 (+4)

Saving Throws Dex +7, Con +15, Wis +10, Cha +11
Skills Arcana +12, Perception +17, Stealth +7
Damage Immunities radiant
Condition Immunities blinded
Senses blindsight 60 ft., darkvision 120 ft., passive Perception 27
Languages Common, Draconic
Challenge 21 (33,000 XP)
Proficiency Bonus +7


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


  • Multiattack. The prismatic dragon uses its Frightful Presence. It then makes one Bite attack and two Claw attacks.
  • Bite. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 18 (2d10 + 7) piercing damage.
  • Claw. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 14 (2d6 + 7) slashing damage.
  • Tail. Melee Weapon Attack: +14 to hit, reach 20 ft., one target. Hit: 16 (2d8 + 7) bludgeoning damage.
  • Frightful Presence. Each creature of the prismatic dragon’s choice that is within 120 feet of the dragon and aware of it must succeed on a DC 19 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.
  • Breath Weapon (Recharge 5–6). The prismatic dragon uses one of the following breath weapons:
    • Light Beam. The prismatic dragon emits a beam of white light in a 120-foot line that is 10 feet wide. Each creature in that line must make a DC 23 Dexterity saving throw, taking 90 (20d8) radiant damage on a failed save, or half as much damage on a successful one.
    • Rainbow Blast. The prismatic dragon emits multicolored light in a 90-foot cone. Each creature in that area must make a DC 23 Dexterity saving throw, taking 72 (16d8) damage on a failed save, or half as much damage on a successful one. The dragon splits the damage up among acid, cold, fire, lightning, or poison, choosing a number of d8s for each damage type totaling 16d8. It must choose at least two damage types.
  • Spellcasting. The prismatic dragon casts one of the following spells, requiring no material components and using Intelligence as the spellcasting ability (spell save DC 20):


The prismatic dragon can take 3 legendary actions, choosing from the options below. Only one legendary action 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 prismatic dragon makes a Wisdom (Perception) check.
  • Tail Attack. The prismatic dragon makes a tail attack.
  • Cast a Spell (Costs 2 Actions). The prismatic dragon uses Spellcasting.
  • Shimmering Wings (Costs 2 Actions). The prismatic dragon beats its wings. Each creature within 20 feet of the dragon must succeed on a DC 19 Wisdom saving throw or take 16 (3d10) radiant damage and become blinded until the start of the dragon’s next turn.


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

  • Crystal Growth. Luminescent quartz and other inexpensive crystal protrude from all surfaces within 6 miles of a prismatic dragon’s lair.
  • Enhanced Spells. Color-based spells (such as hypnotic pattern, frenzied bolt from Deep Magic, or any “prismatic” spell) cast within 1 mile of a prismatic dragon’s lair become enhanced. When rolling damage for a spell of that type that deals damage, treat any 1 on a damage die as a 2 and increase the spell save DC by 1 (this doesn’t affect the dragon’s spells).
  • Prismatic Light. All light sources, including those created by magic effects, shed light in a rainbow of colors while within 1 mile of a prismatic dragon’s lair. If the dragon dies, these effects fade over the course of 1d10 days. The quartz and crystals immediately lose their luminescence and crumble to dust over the same period.


Prismatic dragons inhabit underground caverns, especially those containing colorful, translucent crystals. Some dragons dwell in closed off portions of their mighty caverns, while many construct shrines or cathedrals from the crystals grown in their territories. Though the dragons don’t require light to see, they always dot their lairs with light-filled, crystal globes to enhance the vibrant displays.

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

  • Crystalline Burst. Crystals suddenly grow from a point on the ground the dragon can see within 120 feet of it, creating a 1-foot-tall carpet of crystals. Each creature within 10 feet of that point must make a DC 15 Dexterity saving throw, taking 21 (6d6) piercing damage and falling prone on a failed save, or half as much damage and not falling prone on a successful one. The area becomes difficult terrain, and when a creature moves into or within the area, it takes 2d6 piercing damage for every 5 feet it travels. The crystals crumble to dust when the dragon uses this lair action again or when the dragon dies.
  • Dazzling Lights. Light strobes at a point the dragon can see within 120 feet of it. Each creature other than the dragon that starts its turn within 60 feet of that point must make a DC 15 Charisma saving throw or have disadvantage on attack rolls until the start of its next turn. The effect persists for 1 minute, until the dragon uses this lair action again, or until the dragon dies.
  • Mood Lights. The dragon changes the ambient lighting centered on a point within 120 feet of it. Each creature within 30 feet of that point must succeed on a DC 15 Wisdom saving throw or suffer one of the following effects until initiative count 20 on the next round (the dragon chooses the effect, which applies to all creatures that failed their saving throws, when it uses this lair action): the target becomes apathetic and has disadvantage on attack rolls and ability checks; the target becomes enraged and uses its next action to make a melee attack against a random creature within its reach; the target becomes paranoid and considers no other creature an ally, refusing help and being unable to benefit from the spells and effects of allies. A creature immune to being charmed is unaffected by this effect.


With a multicolored hide and wings with multifaceted panes, this dragon stands over an array of chaotic crystals.

Light gleams off the dragon’s hide and pours through its wings in a dizzying display.

Prismatic dragons bring light and color to the otherwise dark and gray underworld. They consume minerals for sustenance, making them relatively harmless as far as their appetites go, unless they encounter creatures loaded with gems and jewels.

Even then, they may negotiate for the treats, and canny explorers discover worthless crystals satisfy the dragons just as much as valuable jewels.

Resplendent Flightlessness. Like many dragons, prismatic dragons possess wings, but they can’t sustain flight with their wings. Prismatic dragon wings have both the appearance and unwieldiness of stained glass. Fortunately, the dragons have no need to fly in most of their domain and their razor-sharp claws give them strong purchase to climb. The dragons’ wings have a greater purpose than aesthetics—though they are vain about their appearance—because the dragons can tilt their wings to dazzle opponents to the point of blindness. As prismatic dragons age, their bodies shift in coloration from a dusty pink through an ever-expanding panoply of hues, including those invisible to most others.

Crystal Groves. Prismatic dragons tend crystals in their lair and in the surrounding territory. These crystal groves exhibit a riot of different shapes, sizes, and colors. Proud of their carefully cultivated collection, prismatic dragons may become incensed when a visitor criticizes any of the crystals or arrangements. Though prismatic dragons coexist peacefully with crystalline monoliths, the dragons harbor jealousy about the monoliths’ crystal gardens, and they subtly direct intruders to a monolith’s lair in the fervent hope the interlopers damage the other creature’s crystal.

Gregarious Hosts. Of course, all this beauty serves no purpose if only the prismatic dragon can enjoy it. The dragon often welcomes subterranean guests or explorers from the upper world. It can’t promise a comfortable stay for those who have difficulty sleeping on beds of crystals, but it attempts to accommodate food and drink requests within its means. This hospitality ends at undead creatures and conquest-driven groups. A prismatic dragon especially loathes cave dragons and strives to eradicate the crystal-destroying pests if they move into the dragon’s territory.

Section 15: Copyright Notice

Tome of Beasts 3 © 2022 Open Design LLC; Authors: Eytan Bernstein, Celeste Conowitch, Benjamin L. Eastman, Robert Fairbanks, Scott Gable, Basheer Ghouse, Richard Green, Jeremy Hochhalter, Jeff Lee, Christopher Lockey, Sarah Madsen, Ben Mcfarland, Jonathan Miley, Kelly Pawlik, Sebastian Rombach, Chelsea Steverson, Brian Suskind, Mike Welham

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