Ancient Emerald Dragon

Gargantuan dragon (gem), typically lawful neutral

Armor Class

20 (natural armor)

Hit Points

332 (19d20 + 133)

Speed

walk 40 ft., burrow 30 ft., fly 80 ft.

Saves

Dex +4, Con +14, Wis +11, Cha +12

Skills

Arcana +12, Deception +12, Perception +18, Stealth +8

Damage Resistances

fire, psychic

Condition Immunities

frightened, prone

Senses

blindsight 60 ft., darkvision 120 ft.

Languages

Common, Draconic, Telepathy 120 ft.

Challenge

21

Proficiency Bonus

+7

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 can leave a 20-foot-diameter tunnel in its wake.

Warp Perception (1/Day)

The dragon can cast mirage arcane, requiring no spell components and using Intelligence as the spellcasting ability.

Actions

Multiattack

The dragon 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 plus 10 (3d6) psychic damage.

Claw

Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 14 (2d6 + 7) slashing damage.

Disorienting Breath (Recharge 5-6)

The dragon exhales a wave of psychic dissonance in a 90-foot cone. Each creature in that area must make a DC 22 Intelligence saving throw. On a failed save, the creature takes 56 (16d6) psychic damage, and until the end of its next turn, when the creature makes an attack roll or an ability check, it must roll a d8 and reduce the total by the number rolled. On a successful save, the creature takes half as much damage with no additional effects.

Spellcasting (Psionics)

The dragon casts one of the following spells, requiring no spell components and using Intelligence as the spellcasting ability (spell save DC 20): • At will: mage hand (the hand is invisible), minor illusion • 1/Day each: detect thoughts, dispel magic, etherealness, major image, mislead

Change Shape (Bonus Action)

The dragon magically transforms into any creature that is Medium or Small, while retaining its game statistics (other than its size). This transformation ends if the dragon is reduced to 0 hit points or uses a bonus action to end it.

Psychic Step (Bonus Action)

The dragon magically teleports to an unoccupied space it can see within 60 feet of it.

Legendary actions

Legendary Actions (3/Turn)

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.

Claw

The dragon makes one claw attack.

Psionics (Costs 2 Actions)

The dragon uses Psychic Step or Spellcasting.

Emerald Embers (Costs 3 Actions)

The dragon creates a dancing mote of green flame around a creature it can see within 60 feet of it. The target must succeed on a DC 20 Dexterity saving throw or take 42 (12d6) fire damage.