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Monster · SRD 5.2.1

Ancient Blue Dragon

Gargantuan dragon, lawful evil

Armor Class
22
Hit Points
481 (26d20)
Speed
fly 80 ft., 40 ft., burrow 40 ft.
STR
29 (+9)
DEX
10 (+0)
CON
27 (+8)
INT
18 (+4)
WIS
17 (+3)
CHA
25 (+7)
Senses
blindsight 60 ft., darkvision 120 ft., passive perception 27
Languages
Common, Draconic
Challenge
23 (50,000 XP)

Traits

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 Shatter (level 3 version).

Rend. Melee Attack Roll: +16, reach 15 ft. Hit: 18 (2d8 + 9) Slashing damage plus 11 (2d10) Lightning damage.

Lightning Breath (Recharge 5–6). Dexterity Saving Throw: DC 23, each creature in a 120-foot-long, 10-foot-wide Line. Failure: 88 (16d10) Lightning damage. Success: Half damage.

Spellcasting. The dragon casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 22): At Will: Detect Magic, Invisibility, Mage Hand, Shatter (level 3 version) 1/Day Each: Scrying, Sending

Legendary Actions

Cloaked Flight. The dragon uses Spellcasting to cast Invisibility on itself, and it can fly up to half its Fly Speed. The dragon can't take this action again until the start of its next turn.

Sonic Boom. The dragon uses Spellcasting to cast Shatter (level 3 version). The dragon can't take this action again until the start of its next turn.

Tail Swipe. The dragon makes one Rend attack.

Gargantuan dragon, lawful evil

Special Abilities

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 Shatter (level 3 version).

Rend

Melee Attack Roll: +16, reach 15 ft. Hit: 18 (2d8 + 9) Slashing damage plus 11 (2d10) Lightning damage.

Lightning Breath (Recharge 5–6)

Dexterity Saving Throw: DC 23, each creature in a 120-foot-long, 10-foot-wide Line. Failure: 88 (16d10) Lightning damage. Success: Half damage.

Spellcasting

The dragon casts one of the following spells, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 22): At Will: Detect Magic, Invisibility, Mage Hand, Shatter (level 3 version) 1/Day Each: Scrying, Sending

Legendary Actions

Cloaked Flight

The dragon uses Spellcasting to cast Invisibility on itself, and it can fly up to half its Fly Speed. The dragon can't take this action again until the start of its next turn.

Sonic Boom

The dragon uses Spellcasting to cast Shatter (level 3 version). The dragon can't take this action again until the start of its next turn.

Tail Swipe

The dragon makes one Rend attack.

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This work includes material from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.

Reformatted and reorganized for presentation on PostRoll; text unmodified.

Licensed under Creative Commons Attribution 4.0 International.

srd-5.2.1 · Version 1.0.0 · Updated Jul 9, 2026