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Ancient Blue Dragon

Gargantuan · Dragon · CR 23 · Lawful Evil

Source. 5e 2024 Rules

22 (natural armor)

481 (26d20 + 208)

Ability Scores

Core attributes and their modifiers.

STR

DEX

CON

INT

WIS

CHA

Overview

Category Monsters

Size Gargantuan

Type Dragon

Alignment Lawful Evil

XP 50000

Initiative Bonus +14

Movement

Walk 40 ft (12.2 m)

Fly 80 ft (24.4 m)

Swim 20 ft (6.1 m)

Climb 20 ft (6.1 m)

Burrow 40 ft (12.2 m)

Crawl 20 ft (6.1 m)

Senses

Darkvision 120 ft (36.6 m)

Blindsight 60 ft (18.3 m)

Passive Perception 27

Saving Throws

Strength +9 Dexterity +7 Constitution +8 Intelligence +4 Wisdom +10 Charisma +7

Skills

Perception +17 Stealth +7

Languages

Common, Draconic

Resistances & Immunities

Damage Immunities

lightning

Traits

Legendary Resistance (4/Day, or 5/Day in Lair)

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

Actions

Lightning Breath

Recharge 5–6 Cost 1

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

Multiattack

Cost 1

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

Rend

Cost 1

+16 to hit, reach 15 ft (4.6 m). Hit: 2d8+9 slashing plus 2d8 lightning damage.

Melee Attack Roll: +16, reach 15 ft. 18 (2d8 + 9) Slashing damage plus 11 (2d10) Lightning 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
1/Day Each: Scrying, Sending

Legendary Actions

Cloaked Flight

Cost 1

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

Cost 1

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

Cost 1

The dragon makes one Rend attack.

About Ancient Blue Dragon

Ancient Blue Dragon is a gargantuan dragon with a Challenge Rating of 23. It has a lawful evil alignment.

In combat, this creature maintains an Armor Class of 22 and possesses 481 hit points (derived from 26d20 + 208).

Ancient Blue Dragon has communication capabilities including Common, Draconic. This allows it to interact verbally with various creatures and characters.

GM Tips: Using Ancient Blue Dragon

3 tips available

When using Ancient Blue Dragon in your D&D 5e campaign, consider these tactical approaches:

Flight Control Strategy: Target flying creatures with spells like 'Hold Person', 'Web', or 'Grease' to ground them. Without flight restriction, they can escape melee range easily. Consider area denial spells below their flight altitude to force them into disadvantageous positions.
Burrowing Tactics: This creature can burrow at 40 ft. It can ambush from underground or escape combat by digging. Use 'Earthbind' or create difficult terrain to limit burrowing. Consider fighting in areas without soft ground.
Lightning Damage Awareness: Lightning attacks often have long range and high speed. Advise players to use cover and avoid metal armor/weapons. Water surfaces amplify lightning damage - avoid fighting near water.

Player Guide: Facing Ancient Blue Dragon

3 strategies available

When your party encounters this creature, keep these strategies in mind:

Counter Flight Advantage: This creature can fly! Use ranged attacks, reach weapons, or spells like 'Thunderwave' to push it away. Consider 'Gust of Wind' or 'Earthbind' to ground it. Melee characters need fly speed or flight magic to engage.
Burrowing Defense: This creature can burrow at 40 ft! It can ambush from underground. Use 'Earthbind', create difficult terrain, or fight on hard surfaces. 'Stone Shape' can seal burrows.
Lightning Damage Protection: This creature deals lightning damage! Avoid metal armor and weapons. Use cover and avoid water surfaces. 'Iron Skin' or 'Protection from Energy' can help.

Encounter Building Calculator

Standard Party Encounter (4-5 characters):

This creature is a medium encounter for a party of 4 characters of level 23.

High-Level Solo Encounter:

This creature is too powerful for a single level-20 character. You need 3.0 character(s) at maximum level (20) to face this creature.

Experience Point Thresholds:

Medium: 55,200 XP
Hard: 82,800 XP
Deadly: 110,400 XP

Based on D&D 5e Dungeon Master's Guide encounter building guidelines. CR roughly equals party level for medium encounters.

Frequently Asked Questions

What is the challenge rating of Ancient Blue Dragon?: Ancient Blue Dragon has a Challenge Rating of 23, making it appropriate for parties of level 23.0.
What type of creature is Ancient Blue Dragon?: Ancient Blue Dragon is a Gargantuan Dragon, which affects how certain spells and abilities interact with it.
What languages does Ancient Blue Dragon speak?: Ancient Blue Dragon can communicate in Common, Draconic.