Archfey

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

Fey Ancestor. If a creature with the fey ancestry trait makes an attack against the Archfey, they must succeed a DC 15 Wisdom saving throw. If failed, their attack automatically fails. In additon, fey creatures or creatures with the fey ancestry trait have disadvantage on saving throws from spells cast by the Archfey.

Spellcasting. The Archfey is an 18th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 21, +12 to hit with spell attacks). The Archfey has the following Sorceror spells prepared:

Cantrips (at will): Fire Bolt, true strike, Ray of Frost

1st level (4 slots): Witch Bolt, Charm person, Thunderwave, Magic Missile

2nd level (3 slots): Enlarge/Reduce, hold person, invisibility, Misty Step

3rd level (3 slots): Fireball, counterspell, Lightning Bolt, Fear

4th level (3 slots): Dimension Door, Polymorph

5th level (3 slots): Dominate person, Wall of Stone

6th level (1 slot): Eyebite, Sunbeam

7th level (1 slot): Teleport, [spellReverse Gravity[/spell]

8th level (1 slot): Earthquake, Power Word Stun

9th level (1 slot): Gate

Magic Resistance. The Archfey has advantage on saving throws against spells.

Stunning Touch. Melee Spell Attack: +12 to hit, reach 5 ft., one creature. Hit: 10 (3d6) cold damage. The target must succeed on a DC 18 Constitution saving throw or be stunned until the end of the Archfey's next turn.

Rapier Attack. Melee weapon attack. +10 to hit, reach 5 ft., one creature. Hit: 1d8 piercing damage, plus 6d6 force damage.

The Archfey can take 3 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 Archfey regains spent legendary actions at the start of its turn.

Cantrip. The Archfey casts a cantrip.

Stunning Touch (Costs 2 Actions). The Archfey uses its Stunning Touch.

Charming Voice (Costs 2 Actions). The Archfey speaks to one creature it can see within 10 feet of it. The target must succeed on a DC 18 Charisma saving throw against this magic or become charmed for 1 minute. The charmed target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to the Archfey's voice for the next 24 hours.

Mind Erosion (Costs 3 Actions). Each living creature within 20 feet of the Archfey must make a DC 18 Wisdom saving throw against this magic, taking 24 (7d6) psychic damage on a failed save, or half as much damage on a successful one.