Aurlock the ice king

Frost  walker. He can move across ice difficult terrain without taking extra movement 

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

Magic Weapon aurlocks attack are magical in order to overcome resistances 

Ice armour once per day  aurlock can create an icy armour to protect him giving him 100 temporary hit points  but a vulnerability to fire damage until they are depleted 

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

Frostbite.Melee Weapon Attack: [rollable]+18;{"diceNotation":"1] to hit, reach 15 ft., one target. Hit: 19 dealing 2d12 +10 piercing damage + 2d8 cold 

Glacial Claws. Melee Weapon Attack: +18 to hit  every one in a 15ft cone reach  dealing 2d10+10 slashing damage+ 2d6 cold 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.

Frost Breath  every enemy in a 90-foot cone has to make an dc 22 con save as aurlock shoots an frosty blast or take [roll]16d10[/roll] cold damage if they fail half if they succeed 

Aurlock the awakened once per day when aurlock is at 0 hp he can regain 150 hp

The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The dragon regains spent legendary actions at the start of its turn.

Detect. The dragon makes a Wisdom (Perception) check.

Frostbite aurlock gets  to do 1 Frostbite attack 

Blizzard aurlock flaps his wings and ever person in a 15ft cone has to make a dc 22 Dexterity saving throw or take 2d8 bludgeoning damage + 1d12 cold damage and becomes prone