Ancient Blue Dragon

Gargantuan dragon · CR 23 · 50,000 XP

22 AC · 481 HP

Roll the Ancient Blue Dragon

Rend

Lightning Breath DC 23 DEX

Press a roll button. The dice land here.

Stat block

Type: Gargantuan dragon, lawful evil
Armor Class: 22
Hit Points: 481 (26d20 + 208)
Speed: 40 ft., burrow 40 ft., fly 80 ft.
Challenge: 23 (50,000 XP), proficiency +7
Immunities: lightning
Senses: darkvision 120 ft., blindsight 60 ft., passive perception 27
Languages: Common, Draconic

STR	DEX	CON	INT	WIS	CHA
29	10	27	18	17	25

Ancient Blue Dragon odds against your Armor Class

Chance to hit, then average damage per attack once misses and critical hits are counted.

Attack	AC 12	AC 14	AC 15	AC 16	AC 18	AC 20
Rend (+16)	95% 28.6 dmg	95% 28.6 dmg	95% 28.6 dmg	95% 28.6 dmg	95% 28.6 dmg	85% 25.7 dmg
Full turn (3 attacks)	85.6 dmg	85.6 dmg	85.6 dmg	85.6 dmg	85.6 dmg	76.9 dmg

Ancient Blue Dragon hit points

The stat block uses the average, 481. Rolled, 26d20 + 208 lands anywhere from 234 to 728.

234chance of each total for 26d20 + 208728

Hit points	Chance
358 or more	>99%
481 or more	51%
605 or more	<1%
679 or more	<1%

Traits

Legendary Resistance. 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 () Slashing damage plus 11 () Lightning damage.

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

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.

Other CR 23 monsters

Ancient Silver Dragon Kraken

This page includes material from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, available at dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License. The averages, odds and tables are ours.