Valthuur Nightwing

Chill of the void. cold damage  dealt by the Void dragon ignores resistance to cold damage, but not cold immunity.

Collapsing star. When the Void dragon is slain it explodes in a swath of celestial destruction. each Creature, Object and Structure within 1 Mile of the dragon takes 55 (10d10) bludgeoning, 55 (10d10) cold, & 55 (10d10) psychic damage. each damage type can be reduced by half with a successful DC 21 saving throw: Dexterity vs Bludgeoning, Constitusion vs Cold & Wisdom vs Psychic. Additionally, a creature that fails more than 2 saves is affected by the plane shift spell and is sent to a random plane.

Innate spellcasting. the Void dragon's spell casting ability is Charisma (spell attack modifier  +14, spellsave DC 22). The Dragon can innately cast the following spells, requiring no material components.

At will: Magnify gravity, plane shift, sun bolt

3/day: counterspell, disintegrate, pulse wave

1/day: dark star, gravity fissure, gravity sinkhole, singularity, supernova

Improved multiattack defence. when the dragon is hit with an attack it's AC increases by 2 for each attack that same creature makes against the dragon, the AC bonus stacks for each successful attack the creature makes.

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

Void Dweller. Void dragons dwell in the empty expanse between the stars, and do not require air, food, drink, or sleep. when flying between stars the void dragon magically glides on solar winds, making the immense journey through the void in an impossibly short time.

Multiattack. The dragon can use its Aura of Madness. It then makes three attacks: one with its bite and two with its claws.

Bite. Melee Weapon Attack: +16 to hit, reach 15 ft., one target. Hit: 20 (2d10 + 9) piercing damage plus 14 (4d6) cold damage.

Claw. Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit: 16 (2d6 + 9) slashing damage plus 7 (2d6) cold damage.

Tail. Melee Weapon Attack: +16 to hit, reach 20 ft., one target. Hit: 18 (2d8 + 9) bludgeoning damage.

Aura of Madness. Each creature of the dragons choice within 120ft of the dragon and aware of it must succeed on a DC 22 Wisdom saving throw of become frightened for 1 minuete. A creature repeats the saving throw at the end of each of it's turns, ending the effect on itself on a success. If a creature fails the saving throw by 5 of more it is driven insane. an insane creature is frightened permanently, and behaves as if affected by confusion while it is frightened in this way. If a creature's saving throw is successful or the effect ends for the creature it is immune to the dragon's Aura of Madness for the next 24 hours.

Breath weapons. the dragon uses one of it's breath weapons. each breath weapon recharges seperatly.

Disintegrating Ray. (Recharge 5–6).   The dragon exhales fire in a 180-foot line. Each creature in that area must make a DC 24 Constution saving throw, taking 85 (13d6+40) force damage on a failed save, or half as much damage on a successful one, if this attack reduces a creature to 0hp it is disintergrated as it killed by a disintegrate.

Gravitic Breath. (Recharge 5–6).  The dragon exhales a 90ft cube of localized gravity, originating from the dragon. Falling damage in the area increases to 1d10 per 10ft fallen. When a creature starts it's turn within the area of enters the area for the first time in a turn, including when the dragon creates the field, it must succeed a DC 24 Strength saving throw. on a failed save 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 it's turn. The field persists until the dragon's breath recharges, and it can't use gravitic breath twice consecutivly.

Stellar Flare Breath (Recharge 5–6). The dragon exhales fire in a 90-foot cone. Each creature in that area must make a DC 24 Dexterity saving throw, taking 45 (13d6) fire damage Plus 45 (13d6) Radiant damage on a failed save, or half as much damage on a successful one.

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.

Tail Attack. The dragon makes a tail attack.

Void slip (Costs 2 Actions). The dragon beats its wings. Each creature within 15 feet of the dragon must succeed on a DC 21 Dexterity saving throw or take 16 (2d6 + 9) bludgeoning damage and be knocked prone. The dragon can then teleport to an unoccupied space within 40ft.

Void Cache (costs 3 actions). The dragon can magically reach into it's treasure hoard and retreive one item. if the dragon is holding an item, it can use this ability to deposit the item into it's hoard.

Inhale (costs 3 actions). the Dragon inhales all air within a 90ft cone, each creature within the area must succeed a DC 21 Constitution saving throw or start suffocating of a failed save. a suffocating creature had it's Constitution modifer+1 rounds before it is incapacitated, whilst suffocating a creature has disadvantage on saving throws, attack rolls, & ability checks. the Dragon can then roll a D6 on a 4+ it recharges one of it's breath attacks, the air returns to the area 5ft at a time starting from the outer squares of the affected area.

Legendary reactions

Critical defence. when the Dragon is hit with a critcal hit it immediatly can use it's void slip legendary action without a cost

Impoved oppurtunity attack (3/round). the dragon can make a claw attack against a creature that exits it's threat range regardless of if the creatures movement provokes attacks or not. additionally the dragon can make an oppurtunity attack against a creature that crit fails against it or casts a spell within it's reach.

Cosmic slip. when a creature misses an attack against the dragon by 5 or more the dragon can cause the attack to hit the attacker instead.