Sources
CR
Type
Size
Alignment
Movement

Arveiaturace

Gargantuan Dragon, Chaotic Evil

Armor Class 20 (natural armor)
Hit Points 333 (18d20 + 144)
Speed 40 ft., fly 80 ft., swim 40 ft., burrow 40 ft.
STR
26
+8
DEX
10
+0
CON
26
+8
INT
10
+0
WIS
13
+1
CHA
14
+2
Saving Throws DEX +6, CON +14, WIS +7, CHA +8
Skills Perception +13, Stealth +6
Damage Immunities cold
Senses blindsight 60 ft. (blind beyond this radius), darkvision 60 ft., passive Perception 23
Languages Common, Draconic
Challenge 20 (25,000 XP)

Traits

Ice Walk. Arveiaturace 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 (3/Day). If Arveiaturace fails a saving throw, it can choose to succeed instead.

Actions

Multiattack. Arveiaturace can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit:19 (2d10 + 8) piercing damage plus 9 (2d8) cold damage.

Claw. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit:15 (2d6 + 8) slashing damage.

Tail. Melee Weapon Attack: +14 to hit, reach 20 ft., one target. Hit:17 (2d8 + 8) bludgeoning damage.

Frightful Presence. Each creature of Arveiaturace's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 16 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the dragon's Frightful Presence for the next 24 hours.

Cold Breath (Recharge 5–6). Arveiaturace exhales an icy blast in a 90-foot cone. Each creature in that area must make a DC 22 Constitution saving throw, taking 72 (16d8) cold damage on a failed save, or half as much damage on a successful one.

Legendary Actions

Detect. Arveiaturace makes a Wisdom (Perception) check.

Tail Attack. Arveiaturace makes a tail attack.

Wing Attack (Costs 2 Actions). Arveiaturace beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 22 Dexterity saving throw or take 15 (2d6 + 8) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

Lore

Known to Ten-Towners as the White Wyrm, Arveiaturace is an ancient white dragon that lairs atop the Reghed Glacier. She remains the most fearsome predator in Icewind Dale, although age has clouded her eyes with cataracts, limiting the range of her vision to 60 feet. Her blindsight, hearing, and sense of smell are undiminished, however. Fortunately for the residents of the dale, she prefers the taste of reindeer, walrus, and polar bear flesh to that of humanoids. The dragon has a healthy respect…