Ancient Black Dragon
CR 21 Gargantuan dragon dealing 67 acid damage in a 90-foot line (DC 22 DEX save, half on success) via Acid Breath on recharge. Multiattack chains three Rend strikes at +15 reach 1...
Ancient Black Dragon. Gargantuan dragon, chaotic evil.
Languages: Common, Draconic
Traits: Amphibious; Legendary Resistance (4/Day, or 5/Day in Lair)
Gargantuan dragon · chaotic evil
AC 22 · HP 367 · Speed 40 ft., fly 80 ft., swim 40 ft., climb 20 ft. · Initiative +16
| STR | DEX | CON | INT | WIS | CHA | |
|---|---|---|---|---|---|---|
| Score | 27 | 14 | 25 | 16 | 15 | 22 |
| Mod | +8 | +2 | +7 | +3 | +2 | +6 |
| Save | +8 | +9 | +7 | +3 | +9 | +6 |
Skills Perception +16, Stealth +9 · Senses blindsight 60 ft., darkvision 120 ft., passive Perception 26 · Challenge 21 (PB +7)
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
Acid Breath. Dexterity Saving Throw: DC 22, each creature in a 90-foot-long, 10-foot-wide Line. Failure: 67 (15d8) Acid damage. Success: Half damage.
Multiattack. The dragon makes three Rend attacks. It can replace one attack with a use of Spellcasting to cast Acid Arrow (level 4 version).
Rend. Melee Attack Roll: +15, reach 15 ft. 17 (2d8 + 8) Slashing damage plus 9 (2d8) Acid damage.
Spellcasting. 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, Acid Arrow - **1/Day Each:** Create Undead, Speak with Dead, Vitriolic Sphere