Cillaz Ice Fang (Great White Dragon)

Ice Walk: Cillaz 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 (5/Day): If Cillaz fails a saving throw, it can choose to succeed instead.

Ice Shell: Whenever Cillaz takes 25 or more damage he takes no damage instead, unless the damage is fire damage.

Frost Fortitude: Cillaz has 250 additional hit points. 

While any number of this hit points remain he has the following additional benefits.

Resistance to all damage types.

Immunity to all conditions other than grapple, restrained and prone.

Hail Storm Cloak Cillaz has a permanent hail storm surrounding his cold scales, all creatures that move to or start their turn within 30ft of Cillaz must succeed in a DC 18 Constitution saving throw taikung 2d8 cold damage on a failure, half as much on a success,

Additionaly, due to the strong winds and hail ranged attacks made agaist Cillaz or any creature within the affected area are made with disadvantage (Cillaz is immune to this effect).

Cold Mind. Resilient to mind effects, chilling the mind of foes that attempt to target his mind whenever a creature attempts to read, control or charm Cillaz in any way it must succeed in a DC 23 Wisdom saving throw, having its mind flooded with phantasms of Ice and blizzards, taking 2d6 psychic damage and 2d6 cold damage and the spell or spell like effect fails to resolve on a failure, on a success the creature´s spell or spell like effect resolves normaly. 

Multiattack. Cillaz can make four attacks on its attack action, one Ice Fangs attack and two Ice Claws attacks and one Swiping Claws attacks.

Ice Claws. Melee Weapon Attack +15 to hit, 10ft reach, one target for 4d8+8 slashing damage + 2d8 cold damage, a creature hit with this attack must succeed in a DC 23 Strenght saving throw falling prone on a failure.

Ice Fangs. Melee Weapon Attack +15 to hit, 5ft reach, one target for 4d6+8 piercing damage + 2d8 cold damage, a creature hit by this attack must succeed in a DC 23 Strength or Dexterity saving throw being restrained by Cillaz jaws on a failure.

Swiping Claws. Cillaz makes a +15 bonus hit Melee Weapon attack, all creatures within 5ft of Cillaz that are hit with this attack take 2d8+4 slashing damage + 2d8 cold damage, furthermore a creature hit with this attack must  succeed in a DC 23 Strenght saving throw being pushed 5ft away on a failure.   

Blizzard Breath. All creatures within a 120ft long and 15ft wide line from Cillaz must succeed in a DC 23 Dexterity saving throw taking 20d6 cold damage, half as much on a success, a creature that takes damage from this effect must succeed in a DC 23 Constitution saving throw, being partialy frozen in a cover of ice having its speed reduced by half, and disadvantage on dexterity saving throws on a failure , 

Frost Breath (Recharge 3-6). All creatures within a 60ft long 10ft wide line must succeed in a DC 23 Dexterity saving throw taking 25d6 cold damage and being frozen in an ice block on a failure. 

A creature frozen in this way has its speed reduced to 0, is restrained without being able to breath, and cannot take any action on its turn other than atempting to break free by succeeding in a DC 23 Strenght saving throw to break out of the ice.

if a creature frozen in this way takes at least 10 fire damage it also breaks free.

Ice Mirror. Cillaz Swaps its current location with any of its Ice Mirrors within 300ft of it, teleporting into their space.

Refreeze: Cillaz refreezes his body regaining the Ice Shell trait.

Crushing Bite. As a bonus action Cillaz crushes a creature restrained in by its Ice Fangs attack, dealing 4d4+8 piercing damage to it.

Cillaz 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. Cillaz regains spent legendary actions at the start of its turn.

Detect. Cillaz makes a Wisdom (Perception) check.

Claw Attack. Cillaz makes a Ice Claw attack.

Ice Mirror.(Costs 2 Actions) Cillaz uses its Ice Mirror action.

Wing Attack (Costs 2 Actions). Cillaz beats its wings. Each creature within 30 feet of the dragon must succeed on a DC 23 Strenght saving throw being pushed 15ft back and falling prone on a failure, Cillaz can then fly up to half its flying speed.