Great Wyrm White Dragon

Cold Mastery. The dragons movement and vision is not hindered by cold, icy surfaces, snow, wind, or storms. Additionally, the dragon can choose to burrow through snow and ice without leaving a trace.

Legendary Resistance (3/Day). When the dragon fails a saving throw, it can choose to succeed instead. When it does, it sheds some of its scales, which turn to ice. If it has no more uses of this ability, its Armor Class is reduced to 18 until it finishes a long rest.

Heart of Winter. When the dragon is first bloodied, it immediately recharges its breath weapon, if its not already available. Additionally, the damage from the dragons Raging Storm is doubled.

Innate Spellcasting. The dragons spellcasting ability is Charisma (save DC 18). It can innately cast the following spells, requiring no material components. 3/day each:dominate beast, fire shield, animal friendship, sleet storm, 1/day each:control weather, wall of ice, reverse gravity

Multiattack. The dragon attacks once with its bite and twice with its claws. In place of its bite attack it can Spit Ice.

Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 30 (4d10 + 8) piercing damage plus 9 (2d8) cold damage.

Claw. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 21 (3d8 + 8) slashing damage.

Tail. Melee Weapon Attack: +15 to hit, reach 20 ft., one target. Hit: 21 (3d8 + 8) bludgeoning damage and the dragon pushes the target 10 feet away.

Spit Ice. The dragon targets a creature within 60 feet forcing it to make a DC 23 Dexterity saving throw. On a failure the target takes 22 (4d10) cold damage and its speed is reduced to 0 until the end of its next turn. On a success it takes half damage.

Cold Breath (Recharge 5-6). The dragon exhales a 90-foot cone of frost. Each creature in the area makes a DC 23 Constitution saving throw. On a failure it takes 66 (19d6) cold damage and its speed is reduced to 0 until the end of its next turn. On a success it takes half damage.

Tail Attack. When a creature the dragon can see within 10 feet hits the dragon with a melee attack, the dragon makes a tail attack against it.

The dragon can take 3 legendary actions. Only one legendary action can be used at a time and only at the end of another creatures turn. It regains spent legendary actions at the start of its turn.

Roar. Each creature of the dragons choice within 120 feet that can hear it makes a DC 18 Charisma saving throw. On a failure, it is frightened for 1 minute. A creature repeats the saving throw at the end of its turn, ending the effect on itself on a success. When it succeeds on a saving throw or the effect ends for it, it is immune to Roar for 24 hours.

Wing Attack. The dragon beats its wings. Each creature within 15 feet makes a DC 23 Dexterity saving throw. On a failure, it is pushed 10 feet away and knocked prone. The dragon can then fly up to half its fly speed.

Raging Storm (1/Day. For 1 minute, gusts of sleet emanate from the dragon in a 40-foot-radius sphere, spreading around corners. The area is lightly obscured, the ground is difficult terrain, and nonmagical flames are extinguished. The first time a creature other than the dragon moves on its turn while in the area, it must succeed on a DC 18 Dexterity saving throw or take 11 (2d10) cold damage and fall prone (or fall if it is flying).