Adult Green Dragon

Huge Dragon (Chromatic), Lawful Evil

AC: 19

Initiative: +11 (21)

HP: 207 (18d12 + 90)

Speed: 40 ft., fly 80 ft., swim 40 ft.

STR: 23 (+6)
DEX: 12 (+1)
CON: 21 (+5)
INT: 18 (+4)
WIS: 15 (+2)
CHA: 18 (+4)

Saving Throws: Dex +6, Wis +7

Skills: Deception +9, Perception +12, Persuasion +9, Stealth +6

Immunities: poison

Condition Immunities: poisoned

Senses: Blindsight 60 ft., Darkvision 120 ft., Passive Perception 22

Languages: Common, Draconic

CR: 15 (XP 13,000, or 15,000 in lair; PB +5)

Habitat: Forest

Treasure: Arcana

Amphibious.

The dragon can breathe air and water.

Legendary Resistance (3/Day, or 4/Day in Lair).

If the dragon fails a saving throw, it can choose to succeed instead.

Spellcasting.

The dragon casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 17):

At will: Detect Magic, Mind Spike (level 3 version)

1/day: Geas

Actions

Multiattack.

The dragon makes three Rend attacks. It can replace one attack with a use of Spellcasting to cast Mind Spike (level 3 version).

Rend.

Melee Attack Roll: +11, reach 10 ft. Hit: 15 (2d8 + 6) Slashing damage plus 7 (2d6) Poison damage.

Poison Breath (Recharge 5-6).

Constitution Saving Throw: DC 18, each creature in a 60-foot Cone. Failure: 56 (16d6) Poison damage. Success: Half damage.

Legendary Actions

Legendary Action Uses: 3 (4 in Lair). Immediately after another creature's turn, this creature can expend a use to take one of the following actions; it regains all expended uses at the start of each of its turns.

Mind Invasion.

The dragon uses Spellcasting to cast Mind Spike (level 3 version).

Noxious Miasma.

Constitution Saving Throw: DC 17, each creature in a 20-foot-radius Sphere centered on a point the dragon can see within 90 feet. Failure: 7 (2d6) Poison damage, and the target takes a -2 penalty to AC until the end of its next turn. Failure or Success: The dragon can't take this action again until the start of its next turn.

Pounce.

The dragon moves up to half its Speed, and it makes one Rend attack.

Regional Effects

The region containing an adult or ancient green dragon's lair is warped by its presence, creating the following effects:

Beast Spies.
Tiny Beasts magically gain the ability to understand Draconic and can communicate telepathically with the dragon while within 1 mile of the lair.
Poisonous Thicket.
Ordinary plants growing within 1 mile of the lair poison the air around them. Whenever a creature other than the dragon or its allies finishes a Long Rest in that area, it must succeed on a DC 15 Constitution saving throw or have the Poisoned condition for 1 hour.

If the dragon dies or moves its lair elsewhere, these effects end immediately.

Find this creature in the encounter builder

Source: Monster Manual (2025), p. 153 - Licenses and attribution