Archfey

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

Magic Resistance. The Archfey has advantage on saving throws against spells and other magical effects.

Focused. The Archfey can focus on two concentration spells at the same time. In addition, when the Archfey is forced to make a Constitution saving throw for the purpose of maintaining concentration, it makes the roll at advantage. 

Alter Shape. The Archfey can cast the spell alter self at will as a bonus action without any components. In addition, it does not need to maintain concentration on the spell and it last until the Archfey dismisses it.

One with Nature. The Archfey can talk to plants and animals as if it is always under the effect of speak with plants and speak with animals.

Innate Spellcasting. Archfey innate spellcasting ability is Wisdom (spell save DC 21, + 13 to hit with spell attacks). It can innately cast a number of spells, requiring no verbal or material components.

At will: minor illusion, gust, friends, druidcraft, eldritch blast, mending, message, entangle, silent image

5/day: dispel magic, charm person, giant insect, plant growth, cure wounds, tree stride, faerie fire, phantasmal force, phantasmal killer

3/day each: hold monster, heat metal, call lightning, grasping vine, calm emotions, conjure woodland beings

3/day: moonbeam, blight, polymorph, greater invisibility

2/day each: transport via plants, scrying, mass cure wounds, wrath of nature, greater restoration, conjure fey

1/day each: druid grove, wall of thorns, regenerate, reincarnate, feeblemind, control weather, dominate monster, flesh to stone, seeming, hallucinatory terrain

Withering Touch. Melee Spell Attack: +13 to hit, reach 5 ft., one target. Hit: 11 (4d6 + 7) necrotic damage. 

Dark Delirium (1/Day). The Archfey attempts to plunge a creature within 60 feet it can see into an illusionary realm. The creature must make a DC 21 Wisdom saving throw. On a failed save, the creature is either charmed or frightened (the Archfey chooses which) of the Archfey for 1 minute or until its concentration is broken (as if it were concentrating on a spell). The effect ends if the creature takes any damage. Whilst the illusion is active, the creature thinks it is lost in a misty realm, which the Archfey can choose the appearance of. The creature can see and hear only itself, the Archfey and the illusion.

Misty Escape (1/Day). When the Archfey takes damage, it can turn invisible and teleport up to 60 feet to an unoccupied space. The Archfey stays invisible until the start of its next turn or until it makes an attack or casts a spell.

Beguiling Defences. When a creature attempts to charm the Archfay, it can attempt to reverse the charm. The creature must succeed on a DC 21 Wisdom saving throw or be charmed for 1 minute or until it takes 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.

Detect. The Archfey makes a Wisdom (Perception) check.

Cast. The Archfey casts one of its 'At will' spells.

Move. The Archfey moves its full movement speed.

Tree Step (Costs 2 Actions). The Archfey steps through a tree (or plant/plant mass of equal size) and emerges from another tree (or plant/plant mass of equal size) within 120 feet.

Nature Incarnate (Mythic Trait; Recharges after a Short or Long Rest). When the Archfey is reduced to 0 hit points, it doesn't die or fall unconscious. Instead, the surrounding forest grows darker and a storm forms overhead, the Archfey regaining 342 hit points. Additionally, it gains a flying speed of 60 feet as well as gaining resistance to bludgeoning, piercing, and slashing damage.

If the Archfey's mythic trait is active, it can use the options below as legendary actions for 1 hour after using Nature Incarnate:

Flight. The Archfey flies up to its flying speed.

Teleport. The Archfey magically teleports to an unoccupied space it can see or knows of within 120 feet.

Harness Nature (Costs 2 Actions). The Archfey harnesses the energy of the surrounding nature to cause one of is lair actions to happen. It cannot use one that is currently active/just happened.

Call Hounds (Costs 3 Actions). The Archfey either summons 2d4+2 Blink Dogs or 1d4 Yeth Hounds to aid it. The creatures move after the Archfey (losing initiative ties) and treat the Archfey as their master.

Control Storm (Costs 3 Actions). The Archfey takes control of the storm and causes the following effects, which the Archfey is immune to:

• A bolt of lightning strikes the ground within 120 feet of the Archfey. All creatures within 5 feet of the bolt must make a DC 21 Dexterity saving throw, taking 24 (8d6) lightning damage on a failure, or half as much on a success.
• A powerful gust of wind blows through an area within 120 feet in a 15-foot wide and 100-foot long line. All creatures in the wind must make a DC 21 Strength saving throw. On a failure, the creature is knocked prone and pushed to 30 feet in the direction of the wind. If it collides with a solid surface it takes 12 (4d6) bludgeoning damage.