HP 333 (18d20) AC 20 SPD 40 ft., burrow 40 ft., fly 80 ft., swim 40 ft.

Skills

Perception: +13, Stealth: +6

Senses

Blindsight 60 ft., darkvision 120 ft., passive perception 23

Languages

Common, draconic

Damage Immunities

cold

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 moment.

Legendary Resistance (3/Day)

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

Multiattack

The dragon 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 the dragon'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)

The dragon exhales an icy blast in a 90-foot cone. Each creature in that area must make a DC 22 Constitution saving throw, taking 72 (l6d8) cold damage on a failed save, or half as much damage on a successful one.