Aspect of Sardior

Legendary Resistance (5/Day).
If the aspect fails a saving throw, they can choose to succeed instead.
Diamond Iridescence (Recharges after a Short or Long Rest).
If the aspect would be reduced to 0 hit points, their current hit point total instead resets to 500 hit points, they recharges their Diamond Breath and Astral Distortion, and they regains any expended uses of Legendary Resistance. Additionally, the aspect can now use the options in the "Mythic Actions" section for 1 hour. Award a party an additional 155,000 XP (310,000 XP total) for defeating the aspect of Sardior after their Diamond Iridescence activates.

Multiattack.
The aspect makes one Bite attack and two Claw attacks.
Bite.
Melee Weapon Attack: +19 to hit, reach 15 ft., one target. Hit: 22 (2d12 + 10) piercing damage plus 20 (4d10) force damage.
Claw.
Melee Weapon Attack: +19 to hit, reach 10 ft., one target. Hit: 20 (2d10 + 10) slashing damage. If the target is a Huge or smaller creature, it is grappled (escape DC 27) and is restrained until this grapple ends. The aspect can have only one creature grappled in this way at a time.
Diamond Breath (Recharge 5–6).
The aspect exhales iridescent flames in a 300-foot cone. Each creature in that area must make a DC 27 Dexterity saving throw. On a failed save, the creature takes 66 (11d12) damage of a type of the aspect's choosing: force or psychic. On a successful save, the creature takes half as much damage.
Astral Distortion (Recharge 6).
The aspect targets any number of creatures and objects it can see within 1 mile of it. No one target can weigh more than 8,000 pounds, and objects can't be targeted if they're being worn or carried. Each targeted creature must succeed on a DC 27 Strength saving throw or be restrained in the aspect's telekinetic grip. At the end of a creature's turn, it can repeat the saving throw, ending the effect on itself on a success.
At the end of the aspect's turn, it can move each creature or object it has in its telekinetic grip up to 120 feet in any direction, but not beyond 240 feet of itself. In addition, it can choose any number of creatures restrained in this way and deal 60 (10d12) force damage to each of them.

Spellcasting (Psionics).
The aspect casts one of the following spells, requiring no spell components and using Intelligence as the spellcasting ability (spell save DC 27, +19 to hit with spell attack):
• 1/day each: counterspell, detect magic, dispel magic, forcecage, plane shift, reverse gravity, shield, time stop

Change Shape.
The aspect magically transforms into any creature that is Medium or Small, while retaining its game statistics (other than its size). This transformation ends if the aspect is reduced to 0 hit points or uses a bonus action to end it.
Psychic Warp.
The aspect magically teleports to an unoccupied space it can see within 120 feet of it.

The aspect of sardior can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The aspect of sardior regains spent legendary actions at the start of its turn.
• Attack. The aspect makes one Claw or Tail attack.
• Furious Bite (Costs 2 Actions). The aspect makes one Bite attack. If the attack hits a creature, the target must succeed on a DC 27 Wisdom saving throw or become frightened of the aspect until the end of the target's next turn.
• Psionics (Costs 3 Actions). The aspect uses Psychic Warp or Spellcasting.

If the aspect's Diamond Iridescence trait has activated in the last hour, they can use the options below as legendary actions.
• Disintegrating Beam (Costs 2 Actions). The aspect emits a beam of pure force in a 90-foot line that is 10 feet wide. Each creature in that area must make a DC 27 Intelligence saving throw, taking 36 (6d12) force damage on a failed save, or half as much damage on a successful one. The targets are disintegrated if this damage leaves them with 0 hit points.
• Prismatic Breath (Costs 3 Actions). The aspect exhales multicolored rays of light in a 300-foot cone. Each creature in that area must make a DC 27 Dexterity saving throw, For each target, roll a d10 to determine which color ray affects it.
1-Red.
The target takes 60 (12d10) fire damage on a failed save, or half as much damage on a successful one.
2-Black.
The target takes 60 (12d10) acid damage on a failed save, or half as much damage on a successful one.
3-Blue.
The target takes 60 (12d10) lightning damage on a failed save, or half as much damage on a successful one.
4-Green.
The target takes 60 (12d10) poison damage on a failed save, or half as much damage on a successful one.
5-White.
The target takes 60 (12d10) cold damage on a failed save, or half as much damage on a successful one.
6-Indigo.
The target takes 60 (12d10) force damage on a failed save, or half as much damage on a successful one.
7-Violet.
The target takes 60 (12d10) psychic damage on a failed save, or half as much damage on a successful one.
8-Azure.
The target takes 60 (12d10) thunder damage on a failed save, or half as much damage on a successful one.
9-Yellow.
The target takes 60 (12d10) radiant damage on a failed save, or half as much damage on a successful one.
10-Grey.
The target takes 60 (12d10) necrotic damage on a failed save, or half as much damage on a successful one.