Archmage Vyrn

Fey Ancestry. The drow has advantage on saving throws against being charmed, and magic can’t put the drow to sleep.

spell sniper: Vyrn's ranged spell attacks ignore half and 3/4 cover.

Sorcerous Vitality. Vyrn has 20 Sorcery Points. He can use these to empower his spells with 

• Heightened Spell (3 Points): Use this on Reverse Gravity or Mental Prison. In the chaotic soup of Limbo, it is nearly impossible for enemies to find their footing or their focus.

• Transmuted Spell (1 Point): Vyrn can change the damage type of spells (like Fireball or Cone of Cold) to Thunder or Psychic to represent the raw, unstable energy of the Outer Planes.

• Twinned Spell (Variable): Twinning Tasha's Mind Whip or Psychic Lance allows him to shut down multiple "heroes" at once with a single thought.

Potent counterspell:  When Vyrn casts counterspell, he adds his proficiency bonus to the check (+11 total)

Innate Spellcasting. The drow’s innate spellcasting ability is Charisma (spell save DC 20). It can innately cast the following spells, requiring no material components:

At will: dancing lights

1/day each: darkness, faerie fire, levitate (self only)

Spellcasting. The drow is a 18th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 20, +12 to hit with spell attacks). The drow has the following Sorcerer spells prepared:

Cantrips (at will): mage hand, message, [Tooltip Not Found], ray of frost

1st level (4 slots): mage armor, magic missile, shield, witch bolt

2nd level (3 slots): Tasha's mind whip, misty step, mirror image

3rd level (3 slots): counterspell, fireball, Slow

4th level (3 slots): Raulothim's Psychic Lance, greater invisibility

5th level (2 slots): Synaptic Static, cone of cold,wall of force

6th level(1 slot):  disintegrate, globe of invulnerabilityMental Prison

7th level (1slot):  reverse gravity, teleportpower word pain

8th level (1 slot):  Reality Break (cast before combat)

9th level (1 slot):  power word kill

Staff of Unmaking Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 2 (1d6 − 1) bludgeoning damage, or 3 (1d8 − 1) bludgeoning damage if used with two hands, plus 21 (1d6) force damage.

Chaos Ripple: On a hit, the target must succeed on a DC 20 Strength saving throw or be pushed 10 feet in a random direction as gravity momentarily fails around them.

Limbo's Embrace:  Vyrn casts Reverse Gravity without components.  he can choose up to 3 allies to be unaffected

Arcane Barrage:  Vyrn shoots 5 darts of force from his Staff.  Each Dart hits a creature he can see within 120ft.  Hit:  10(1d8+6) force damage per dart.  If a target is hit by three or more darts, they are poisoned 

Crown of the Slaad Lord (Recharge 5–6). Vyrn targets one creature he can see within 120 feet. The target must succeed on a DC 20 Wisdom saving throw or be struck by a crown of jagged, glowing chaos-matter. While "crowned," the creature is charmed by Vyrn. On each of its turns, the creature must use its action to make a melee attack against a creature other than itself that Vyrn mentally chooses. The creature can repeat the saving throw at the end of each of its turns, ending the effect on a success.

Reaction: Mana Burn. When a creature Vyrn can see within 60 feet casts a spell, Vyrn can force them to make a Charisma saving throw (DC 20). On a failure, the creature takes 1d6 force damage per level of the spell cast, and the spell fails if it was 4th level or lower.

The Triumvirate share a pool of 3 legendary actions. Only one legendary action can be used at a time and only at the end of another creature's turn.

• Warp Fate (Kaelos): One creature Kaelos can see must reroll its last attack roll or saving throw.

• Vile Recovery (Ssethra): Ssethra heals herself or an ally she can see within 60 feet for 20 (4d8 + 2) hit points.

• Shift Position (Vyrn): Vyrn or an ally teleports up to 30 feet to an unoccupied space he can see.