Monster
Ancient Black Dragon
Official reference · XMM · 2024
- Creature type
- Dragon
- Size
- Gargantuan
- Armor class
- 22
- Hit points
- 367 (21d20 + 147)
- Speed
- Walk 40 ft., Fly 80 ft., Swim 40 ft.
- Challenge rating
- 21
- Alignment
- Chaotic Evil
- Strength
- 27
- Dexterity
- 14
- Constitution
- 25
- Intelligence
- 16
- Wisdom
- 15
- Charisma
- 22
- Passive Perception
- 26
- Initiative
- +16
- Saving Throws
- dex: +9; wis: +9
- Skills
- perception: +16; stealth: +9
- Senses
- Blindsight 60 ft., Darkvision 120 ft.
- Languages
- Common, Draconic
- Immunities
- acid
Traits
Amphibious
The dragon can breathe air and water.
Legendary Resistance (4/Day, or 5/Day in Lair)
If the dragon fails a saving throw, it can choose to succeed instead.
Actions
Multiattack
The dragon makes three Rend attacks. It can replace one attack with a use of Spellcasting to cast Melf's Acid Arrow (level 4 version).
Rend
Melee Attack: +15, reach 15 ft. Hit: 17 (2d8 + 8) Slashing damage plus 9 (2d8) Acid damage.
Acid Breath (Recharge 5–6)
Dexterity Saving Throw: DC 22, each creature in a 90-foot-long, 10-foot-wide Line. Failure: 67 (15d8) Acid damage. Success: Half damage.
Legendary action uses: 3 (4 in its lair). The creature can use one option at the end of another creature’s turn and regains spent uses at the start of its turn.
Legendary actions
Cloud of Insects
Dexterity Saving Throw: DC 21, one creature the dragon can see within 120 feet. Failure: 33 (6d10) Poison damage, and the target has Disadvantage on saving throws to maintain Concentration until the end of its next turn. Success or Failure: The dragon can't take this action again until the start of its next turn.
Frightful Presence
The dragon uses Spellcasting to cast Fear. 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.
The dragon casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 21, +13 to hit with spell attacks):
At will: Detect Magic, Fear, Melf's Acid Arrow (level 4 version)
1/day each: Create Undead, Speak with Dead, Vitriolic Sphere (level 5 version)
Regional effects
The region containing an adult or ancient black dragon's lair is warped by its presence, creating the following effects:
- Acrid Haze: Odorous and stifling fog covers the area within 1 mile of the lair, rendering that area Lightly Obscured. Travel for creatures other than the dragon and its allies takes twice the usual time in that area.
- Foul Water: Water sources within 1 mile of the lair are supernaturally fouled. A creature that drinks such water 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.