Cryonax, Frost's Fury

Legendary Resistance (3/Day). If Cryonax fails a saving throw, it can choose to succeed instead.

Primordial Force. Cryonax's weapons are considered magical for the purposes of overcoming Resistance and immunity to magical damage.

Magic Resistance. Cryonax has advantage on saving throws against spells and other magical effects.

Icy Body. When a creature starts its turn within 30 feet of Cryonax, that creature takes 14 (4d6) cold damage. When a creature attacks Cryonax with a melee attack, that creature takes 28 (8d6) cold damage.

Snow Stride.  Once per turn, Cryonax can walk into one snow-covered space and appear up to 500 feet away in another snow-covered space as long as there is a path of snow and ice between them.

Icy Coating. When a spell targets Cryonax, roll a D6. On a 1-2, the spell deals half damage to Cryonax. On a 3, the spell does nothing to Cryonax. On a 4-5, Cryonax redirects the targeting to one other creature within a 50-ft. sphere of Cryonax. 

Multiattack: Cryonax makes up to four attacks: three with his crushing cold and one with his cold breath.

Crushing Cold. Ranged Weapon Attack: +19 to hit, range: 60/300 ft., 10 ft. radius. Hit: 35 (6d8+8) cold damage.

Cold Breath. (Recharge 5-6) Cryonax exhales an icy blast in a 90-foot cone. Each creature in that area must make a DC 24 Constitution saving throw, taking 67 (15d8) cold damage on a failed save, or half as much damage on a successful one.

Cryonax 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. Cryonax makes a Wisdom (Perception) check.

Rage of Ice(Costs X Actions). Cryonax uses his crushing cold attack X times.