Arauthator (Old White Death)

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.

Ice Stride. Arauthator can move through nonmagical ice and snow as if it were difficult terrain without squeezing. While doing so, he leaves no tunnel or sign of his passage.

Legendary Resistance (4/Day, or 5/Day in Lair). If the dragon fails a saving throw, it can choose to succeed instead.

Master of the Frozen Deep. Arauthator's cold damage treats immunity to cold damage as resistance. Creatures with resistance to cold damage take normal damage from his spells and breath weapon.

Multiattack. Arauthator makes one Bite attack and two Claw attacks. He can replace one Claw attack with a use of Spellcasting.

Bite. Melee Weapon Attack: +13 to hit, reach 15 ft., one target. Hit: 18 (2d10 + 7) piercing damage plus 9 (2d8) cold damage.

Claw. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 14 (2d6 + 7) slashing damage.

Tail. Melee Weapon Attack: +13 to hit, reach 20 ft., one target. Hit: 16 (2d8 + 7) bludgeoning damage.

Cold Breath (Recharge 5–6). Arauthator exhales an icy blast in a 90-foot cone. Each creature in that area must make a DC 20 Constitution saving throw, taking 63 (14d8) cold damage on a failed save, or half as much damage on a successful one. A creature killed by this damage becomes a frozen statue.

Spellcasting (Sorcerer). Arauthator casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 17):

• At will: Ray of Frost (3d8 damage), Fog Cloud, Gust of Wind

• 2/day each: Ice Storm, Sleet Storm, Misty Step

• 1/day each: Wall of Ice, Cone of Cold

Frozen Glare. Arauthator targets one creature he can see within 60 feet of him. The target must succeed on a DC 17 Wisdom saving throw or be Frightened of Arauthator until the end of its next turn. If the target fails the save by 5 or more, it is also Restrained by rapidly growing ice crystals while Frightened in this way.

Glacial Shield. When Arauthator is hit by an attack, he creates a momentary shield of hard ice. He adds 5 to his AC against that attack. If the attack misses, the attacker takes 7 (2d6) cold damage from the shattering ice.

Legendary Action Uses: 3 (4 in Lair). Immediately after another creature’s turn, the dragon can expend a use to take one of the following actions. The dragon regains all expended uses at the start of each of its turns.

Wing Attack (Costs 2 Actions). Arauthator beats his wings. Each creature within 15 feet of him must succeed on a DC 21 Dexterity saving throw or take 14 (2d6 + 7) bludgeoning damage and be knocked Prone. Arauthator can then fly up to half his flying speed.

Cast a Spell (Costs 2 Actions). Arauthator uses his Spellcasting feature to cast a spell of 1st or 2nd level (e.g., Misty Step or Gust of Wind).