Adult Ivory Void Dragon

Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.
Chill of the Void. Cold damage dealt by the void dragon ignores resistance to cold damage, but not cold immunity.
Void Dweller. Movement speed doubles when entering the void

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: +13 to hit, reach 10 ft., one target. Hit: 19 (2d10 + 8) piercing damage.

Claw. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 15 (2d6 + 8) slashing damage.

Tail. Melee Weapon Attack: +13 to hit, reach 15 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 18 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.

Breath Weapons (Recharge 5–6). The dragon uses one of the following breath weapons.

Cold Breath. The dragon exhales an icy blast in a 60-foot cone. Each creature in that area must make a DC 20 Constitution saving throw, taking 58 (13d8) cold damage on a failed save, or half as much damage on a successful one.

Gravity Breath. The dragon exhales a 60-foot cube of powerful localized gravity, originating from the dragon. Falling damage in the area increases to 1d10 per 10 feet fallen. When a creature starts its turn within the area or enters it for the first time in a turn, including when the dragon creates the field, must make a DC 20 Dexterity saving throw. On a failure the creature is restrained. On a success the creature’s speed is halved as long as it remains in the field. A restrained creature repeats the saving throw at the end of its turn. The field persists until the dragon’s breath recharges, and it can’t use gravity breath twice consecutively.

Stellar Flare Breath. The dragon exhales star fire in a 60- foot cone. Each creature in that area must make a DC 20 dexterity saving throw, taking 31 (9d6) fire damage and 31 (9d6) radiant damage on a failed save, or half as much damage on a successful one.

Change Shape. The dragon magically polymorphs into a humanoid or beast that has a challenge rating no higher than its own, or back into its true form. It reverts to its true form if it dies. Any equipment it is wearing or carrying is absorbed or borne by the new form (the dragon's choice).

In a new form, the dragon retains its alignment, hit points, Hit Dice, ability to speak, proficiencies, Legendary Resistance, lair actions, and Intelligence, Wisdom, and Charisma scores, as well as this action. Its statistics and capabilities are otherwise replaced by those of the new form, except any class features or legendary actions of that form.

Void Twist. When the dragon is hit by a ranged attack it can create a small rift in space to increase its AC by 2 against that attack. If the attack misses because of this increase the dragon can choose a creature within 30 feet to become the new target for that attack. Use the original attack roll to determine if the attack hits the new target.

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.

Tail Attack. The dragon makes a tail attack.

Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 10 feet of the dragon must succeed on a DC 21 Dexterity saving throw or take 15 (2d6 + 8) bludgeoning damage and be knocked prone. The dragon can then fly up to half its flying speed.

Void Cache (Costs 3 Actions). The dragon can magically reach into its treasure hoard and retrieve one item. If it is holding an item, it can use this ability to deposit the item into its hoard.