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Ancient Blue Dragon

Gargantuan · Dragon · CR 20 · Chaotic Evil

Source. Black Flag SRD

21 (natural armor)

355

Ability Scores

Core attributes and their modifiers.

STR

DEX

CON

+14

INT

WIS

CHA

+11

Overview

Category Monsters

Size Gargantuan

Type Dragon

Alignment Chaotic Evil

XP 25000

Initiative Bonus +6

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)

Passive Perception 19

Saving Throws

Strength +9 Dexterity +6 Constitution +14 Intelligence +4 Wisdom +9 Charisma +11

Languages

Common,Draconic

Resistances & Immunities

Damage Immunities

lightning

Traits

Charged Hide

When the blue dragon hasn't exhaled its Lightning Breath, the electric charge builds up across its body. While the dragon's Lightning Breath is available, it emits wild sparks of electricity, and each creature that starts its turn within 30 feet of the dragon must succeed on a DC 22 CON save or be incapacitated until the start of its next turn.

Legendary Resistance (3/Day)

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

Actions

Bite

+15 to hit, reach 15 ft (4.6 m). Hit: 2d10+9 plus 2d10 lightning damage.

Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 20 (2d10+9) piercing damage plus 11 (2d10) lightning damage.

Claw

+15 to hit, reach 10 ft (3 m). Hit: 2d6+9 slashing damage.

Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 16 (2d6+9) slashing damage.

Elemental Roar (Costs 2 Actions)

The dragon roars at up to two creatures of its choice within 120 feet of it. Each target must succeed on a DC 19 CHA save or be vulnerable to lightning damage until the end of its next turn. A target resistant to lightning damage isn't resistant to it for the duration. A target immune to lightning damage is still immune to it, even if the target fails the save.

Frightful Presence

Each creature of the dragon's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 19 WIS save or be frightened for 1 minute. A creature can repeat the save at the end of each of its turns, ending the effect on itself on a success. If a creature's save is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Lightning Breath

Recharge 5–6

The dragon exhales lightning in a 120-foot line that is 10 feet wide. Each creature in that line must make a DC 22 DEX save, taking 99 (18d10) lightning damage on a failed save, or half as much damage on a successful one.

Multiattack

The dragon uses its Frightful Presence. It then makes one Bite attack and two Claw attacks.

Tail

+15 to hit, reach 20 ft (6.1 m). Hit: 2d8+9 bludgeoning damage.

Melee Weapon Attack: +15 to hit, reach 20 ft., one target. Hit: 18 (2d8+9) bludgeoning damage.

Wing Attack (Costs 2 Actions)

The dragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 23 DEX save or take 16 (2d6+9) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed without provoking opportunity attacks.

Legendary Actions

Detect

Cost 1

The dragon automatically detects every creature and trap within 30 feet of it, pinpointing the current location of each.

Elemental Roar

Cost 2

Tail Attack

Cost 1

The dragon makes a Tail attack.

Wing Attack

Cost 2

About Ancient Blue Dragon

Ancient Blue Dragon is a gargantuan dragon with a Challenge Rating of 20. It has a chaotic evil alignment.

In combat, this creature maintains an Armor Class of 21 and possesses 355 hit points (derived from None).

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 20.

High-Level Solo Encounter:

This creature is too powerful for a single level-20 character. You need 2.0 character(s) at maximum level (20) to face this creature.

Experience Point Thresholds:

Medium: 42,000 XP
Hard: 63,000 XP
Deadly: 84,000 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 20, making it appropriate for parties of level 20.0.
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.