Chaos the star eater

Unusual Nature. Chaos doesn’t require food, sleep, air, or drink

Legendary Resistance (6/Day). If chaos fails a saving throw, it can choose to succeed instead.

Elemental incarnation. fire, cold, lightning, radiant, and force damage dealt by Chaos ignores immunity and resistance to fire, cold, lightning, radiant, psychic ,and force damage.

Limited Magic Immunity. Chaos can't be affected or detected by spells of 6th level or lower unless it wishes to be. It has advantage on saving throws against all other spells and magical effects.

Starblast Burst.  When reduced to 0 hp or leaves combat and after one round passes, the point it was at releases a burst of roiling flames, radiant energy, and force in a mile radius of it . Each creature in that area must make a DC 26 Dexterity saving throw. On a failed save, a creature takes 100 (20d10) force damage, 100 (20d10) fire damage, 100 (20d10) radiant damage and is pushed up to 30 feet away from chaos and knocked prone. On a successful save, a creature takes half as much damage with no other effects. If a creature is reduced to 0 hit points by this effect, the creature immediately dies, and its body is reduced to ash. Additionally, all structures and item (magical ones like artifacts) within range are destroyed completely.

Calescent Aura. At the start of Chaos turn, Chaos can force any number of creatures of his choice within 10 feet of himself to make a DC 20 Constitution saving throw. On a failed save, a creature takes 10 (2d8) fire damage and 10 (2d8) force. 

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

Bite. Melee Weapon Attack: +18 to hit, reach 15 ft., one target. Hit: 20 (2d12 + 9) piercing + (4d10) force damage

Claw. Melee Weapon Attack: +18 to hit, reach 10 ft., one target. Hit: 16 (2d10 + 9) slashing damage.

Tail. Melee Weapon Attack: +18 to hit, reach 20 ft., one target. Hit: 18 (2d8 + 9) bludgeoning damage.

Frightful Presence. Each creature of the chaos's choice that is within 120 feet of the chaos and aware of it must succeed on a DC 24 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 chaos's Frightful Presence for the next 24 hours.

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

Chaos Breath. Chaos exhales lightning in a 120-foot line that is 10 feet wide. Each creature in that line must make a DC 24 Dexterity saving throw, taking 96 (16d12) force damage on a failed save, or half as much damage on a successful one.

Repulsion Breath. Chaos exhales repulsion energy in a 30-foot cone. Each creature in that area must succeed on a DC 24 Strength saving throw. On a failed save, the creature is pushed 60 feet away from the dragon.

Change Shape. Chaos 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 chaos’s choice).

In a new form, chaos 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.

Chaos Spear (recharge 5-6). chaos creates four spears of magical force. Each spear hits a creature of chaos’s choice it can see within 120 feet of it. The target must make a dc 24 constitution saving throw. On a failure, the target must role a (1d4) and it takes 76 (10d10) force damage. If the number for the (1d4) is even the target is paralyzed and can attempt the save at the start of its turns, on a success it is not paralyzed. If the number on the (1d4) is odd, the target takes 1 level of exhaustion that last for 1 hour. This exhaustion can be removed by magic like a greater restoration or similar magic.

roar of dimensional shattering (recharge 5-6). Chaos creates 1d4 portals to the far realm that appear at different points within 120ft of chaos. All creatures within 20ft of the portal must make a dc 24 wisdom save when the portals appear or they start their turn in the area. On a failure, the target takes 76 (10d10) psychic damage and stunned for 1d4 rounds. On a success, the target only takes half damage and is not stunned.

times folly (1/day). Chaos disrupts time within a mile radius of it. All creatures within range must make a DC 25 constitution saving throw. On a failure, it takes 76 (16d10) necrotic damage and suffers the effects of the slow spell for 1 minute. This effect can be removed by magic like a greater restoration or similar magic. On a success, the target only half damage and isn’t slowed.

Chaos can take up to five reactions per round but only one per turn.

gravity twist. when Chaos is hit by a range attack, it can use its powers to create a portal to increase its AC by 6 against that attack. if the attack misses because of this increase, Chaos can choose a creature within 30ft to become the new target for that attack. Use the original attack roll to determine if the attack hits the new target.

Primal Counterspell. Chaos use powerful magic to interrupt a creature that is casting a spell. No matter what level the spell, it fails and has no effect. Whatever the spell’s level, the caster takes 10 (2d8) psychic damage per level of the spell.

The dragon can take 5 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.

Pursuit. Ember moves up to 40 feet in a straight line toward one creature he can see. This movement ignores opportunity attacks.

Forceful Bite (Costs 1 Action). Chaos makes one Bite attack. If the attack hits, it deals an additional 12 (2d10) force damage.