Vaelith, The Fallen Star

Unchained Presence. Enimes within 30ft of Vaelith must succeed on a DC 21 Wisdom save or be stunned until the start of their next turn as their mind is overwhelmed by celestial and abyssal whispers

Innate Spellcasting. Charisma-based, DC 21:
At will: [Greater Invisibility], [Teleport], [Plane Shift]
3/day: [Time Stop], [Dominate Monster], [Reverse Gravity]
1/day: [Wish] (Can only reshape reality related to celestial or abyssal forces)

Multiattack. Vaelith makes four Celestial Blade attacks or uses Abyssal Cataclysm

Celestial Blades. Melee Weapon Attack: +14 to hit, reach 10 ft., 1 target. Hit: 27 (5d6 + 7) [radiant, necrotic, or psychic] damage.

Abyssal Cataclysm (Recharge 5-6). Vaelith unleashes celestial-abyssal energy in a 40ft radius.  Creatures must make a DC 21 Dexterity saving throw, taking 4d10 radiant, 4d10 necrotic, and 4d10 psychic damage on a failed save, half on a success.

Mythic Resistance. When Vaelith fails a saving throw, they can choose to succeed instead (3/day).

Vaelith can take up to three legendary actions per round, choosing from the options below. She can use only one at a time and only at the end of another creature’s turn. She regains spent legendary actions at the start of her turn.  She cannot use the same action twice in a row.

Abyssal Blink (Costs 1 Action). Vaelith teleports up to 40 feet to an unoccupied space she can see. Until the start of her next turn, attacks against her have disadvantage.

Celestial Riposte (Costs 1 Action). When a creature misses an attack against Vaelith, she can immediately make a Celestial Blade attack against them.

Falling Star Strike (Costs 2 Actions). Vaelith moves up to her full speed without provoking opportunity attacks and makes two Celestial Blade attacks against different creatures within reach.

Unravel Reality (Costs 2 Actions). Vaelith chooses a point within 60 feet. A 10-foot radius sphere warps with celestial and abyssal energy. Creatures inside must make a DC 21 Intelligence saving throw or take 33 (6d10) psychic damage.

Final Gambit (Costs 3 Actions, Once per Long Rest)

Vaelith shatters the fragile balance of her celestial-abyssal essence, unleashing a final act of defiance. This action permanently alters her form and comes with severe consequences. She chooses one of two effects—but once she does, her body begins to unravel at the start of each of her turns, forcing her to make death saves at the end of every round, regardless of HP. She can only be stabilized with powerful magic (such as a Wish spell or divine intervention).

Celestial Ascension – The Dying Star

Vaelith erupts in divine radiance, regaining 100 hit points and shedding blinding light in a 60-foot radius.
All creatures within 30 feet must make a DC 21 Constitution saving throw or be blinded and deafened for 1 minute (save ends at end of turns).
Until she dies or the battle ends, all her attacks deal an additional 4d10 radiant damage

Abyssal Devourer – The Abyss Stares Back

Vaelith shreds the life force from all creatures within 30 feet, forcing them to make a DC 21 Constitution saving throw or take 66 (12d10) necrotic damage, healing Vaelith for half the damage dealt.
Any creature that fails by 5 or more suffers a level of exhaustion as their soul withers.
Her physical form fractures, causing her maximum HP to decrease by 15 every round as the abyss consumes her.
At the start of her turn, she must succeed on a DC 18 Wisdom saving throw or lose control, attacking the nearest creatures—friend or foe.

Fate-Sealing Effect:
If Vaelith is reduced to 0 HP after using Final Gambit, she does not fall unconscious—she detonates.

• If she used Celestial Ascension, she explodes in a nova of divine fire, dealing 88 (16d10) radiant damage to everything within 60 feet before fading into nothingness.

• If she used Abyssal Devourer, she collapses into a void rift, dragging everything within 20 feet into an abyssal prison, forcing a DC 21 Strength save to avoid being pulled in.