Ancient White Dragon
gargantuan dragon, chaotic evil
AC 20
Initiative +0 (10)
HP 333 (18d20 + 144)
Speed 40 ft., Swim 40 ft., Burrow 40 ft., Fly 80 ft.
Skills Perception +13, Stealth +6
Immunities cold
Senses Blindsight 60 ft., Darkvision 120 ft. Passive Perception 23
Languages Common, Draconic
CR 20 (XP 25,000; PB +6)
Ice Walk. The dragon can move across and climb icy surfaces without needing to make an ability check. Additionally, Difficult Terrain composed of ice or snow doesn't cost it extra movement.
Legendary Resistance (4/Day, or 5/Day in Lair). If the dragon fails a saving throw, it can choose to succeed instead.
Actions
Cold Breath (Recharge 5-6). Constitution Saving Throw: DC 22, each creature in a 90-foot Cone. Failure: 63 (14d8) Cold damage. Success: Half damage.
Multiattack. The dragon makes three Rend attacks.
Rend. Melee Attack Roll: +14, reach 15 ft. 17 (2d8 + 8) Slashing damage plus 7 (2d6) Cold damage.
Legendary Actions
Freezing Burst. Constitution Saving Throw: DC 20, each creature in a 30-foot-radius Sphere [Area of Effect]|XPHB|Sphere centered on a point the dragon can see within 120 feet. Failure: 14 (4d6) Cold damage, and the target's Speed is 0 until the end of the target's next turn. Failure or Success: The dragon can't take this action again until the start of its next turn.
Frightful Presence. The dragon casts Fear, requiring no Material components and using Charisma as the spellcasting ability (spell save DC 18). The dragon can't take this action again until the start of its next turn.
Pounce. The dragon moves up to half its Speed, and it makes one Rend attack.
Ancient White Dragon is from the System Reference Document 5.2.1 (“SRD 5.2.1”) by Wizards of the Coast LLC, used under the Creative Commons Attribution 4.0 International License. Full attribution is on the Licenses & Attribution page.