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

Spellcasting. The archfey's innate spellcasting ability is Charisma (spell save DC 18). It can innately cast the following spells, not requiring material components:
At will: minor illusion 
1/day: faerie fire, alter self, conjure fey, plane shift, feeblemind

Spellcasting. The archfey is a 16th level spellcaster. Its spellcasting ability is Charisma (spell save DC 18, +10 to hit with spell attacks). It has the following spells prepared: 
Cantrips (at will): friends, message, prestidgitation, dancing lights, eldritch blast
1st level (4 slots): armor of agathys, sleep, hex
2nd level (3 slots): moonbeam, crown of madness, calm emotions
3rd level (3 slots): counterspell, blink, bestow curse
4th level (3 slots): banishment, greater invisibility
5th level (2 slots): seeming, dominate person, scrying
6th level (1 slot): eyebite, mass suggestion
7th level (1 slot): prismatic spray, etherealness
8th level (1 slot): power word stun

Subtle Spell (5/rest). When the archfey casts a spell, it can do so without any somatic or verbal components.

Multiattack. The archfey makes two attacks with its longbow or rapier.

Rapier. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 2) piercing damage. 

Longbow. Ranged Weapon Attack: +7 to hit, range 150/600 ft., one target. Hit: 6 (1d8 + 2) piercing damage.

Fey Presence. Each creature of the archfey's choice that is within 30 feet and aware of it must succeed on a DC 18 Wisdom saving throw or become charmed or frightened (archfey's choice) for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the archfey's Fey Presence for the next 24 hours.

Dark Delirium (Recharges after a Short or Long Rest). A creature of the archfey's choice that it can see within 60 feet of it must make a DC 18 Wisdom saving throw. On a failed save, the creature is charmed or frightened (archfey's choice) for 1 minute or until the archfey's concentration is broken (as if concentrating on a spell). This effect end early if the creature takes any damage. Until this illusion ends, the creature thinks it is lost in a misty realm. The creature can see and hear only itself, the archfey, and the illusion.

Misty Escape (Recharges after a Short or Long Rest). In response to taking damage, the archfey can turn invisible and teleports up to 60 feet to an unoccupied space it can see. It remains invisible until the start of the next turn or until it attacks, makes a damage roll, or casts a spell.

Beguiling Defenses. In response to another creature attempting to charm it, the archfey can attempt to turn the charm back on that creature. The creature must succeed a DC 18 Wisdom saving throw or be charmed for 1 minute or until the creature takes any damage.

Bend Luck (3/day). In response to another creature that the archfey can see making an attack roll, ability check, or saving throw, it can roll 1d4 and apply the number rolled as a bonus or penalty to the creature's roll. It can do so after the creature rolls but before any effects of the roll occur.

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 turns.

Attack. The archfey makes one weapon attack.

Shimmering Shield (Costs 2 Actions). The archfey creates a shimmering, magical field around itself or another creature it can see within 60 feet of it. The target gains a +2 bonus to AC until the end of the archfey's next turn.

Misty Step (Costs 2 Actions). Disappearing in a shroud of silvery mist, the archfey teleports 30 feet to an unoccupied space it can see.