Ancient Emerald Dragon

Gargantuan dragon, chaotic neutral

Armor Class

22 (natural armor)

Hit Points

252 (24d20)

Speed

40 ft., fly 80 ft. (hover), swim 40 ft.

STR

21 (+5)

DEX

24 (+7)

CON

10 (+0)

INT

24 (+7)

WIS

16 (+3)

CHA

22 (+6)

Damage Immunities

fire, lightning

Damage Resistances

bludgeoning, slashing, and piercing from nonmagical attacks

Damage Vulnerabilities

psychic

Senses

blindsight 60 ft., darkvision 120 ft., passive Perception 27

Saving Throws

Dex +14, Int +14, Wis +10, Cha +13

Skills

Arcana +14, Insight +10, Perception +10, Religion +14

Languages

Common, Draconic, telepathy 120 ft.

Challenge

21 (33,000 XP)

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

Interference Aura. Enemies within 30 feet must make a DC 22 Intelligence saving throw every round to maintain spells that require concentration.

Psionics

Charges: 24

Recharge: 1d10

Fracture: 27

Actions

Multiattack. The dragon makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +12 to hit, reach 15 ft., one target. Hit: 16 (2d10 + 5) piercing damage.

Claw. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 12 (2d6 + 5) slashing damage.

Tail. Melee Weapon Attack: +12 to hit; reach 20 ft., one target. Hit: 14 (2d8 + 5) bludgeoning damage.

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.

Psionics. The dragon uses a psionic ability.

Psionic Shift (Costs 2 Actions). The dragon releases a wave of telekinetic energy from its mind. Every creature within 15 feet must make a DC 24 Intelligence saving throw or take 14 (2d6 + 7) force damage and be knocked prone. The dragon then can move up to half its movement 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.

The dragon summons a water elemental.
The dragon casts control water (save DC 22). It does not require concentration to maintain.
The dragon casts thunderwave with DC 22. The area is a 30-foot cube, and the damage is 4d8.

Regional Effects

Intelligent creatures who sleep within 12 miles of an emerald dragon’s lair dream of unending depths, tidal waves, starfish and crustaceans, or a calm sea under solid white sky with constellations under the waters.