Legendary Resistance (4/Day). If the Archfey fails a saving throw, it can choose to succeed instead.

One with Water: The Queen of River Reeds can turn her form into water as a bonus action. Her movement speed doubles and she cannot be damaged while in this form short of destroying the water she is in. She cannot make any form of spellcasting or attack actions while in this form. While not in this water form, she has a swim speed equal to her movement speed, and she can breath underwater.

Giver of Boons. If a male Fey-touched creature is able to successfully catch her interest, she will grant them a portion of her power. She will enter into a contract to be a Patron to a Warlock.

Reincarnation. If killed, she turns into water for 10 days. At which point, she takes over another water based Fey (Nymph, Lorelei, Siren, etc.). It takes 1 month for her to reform herself into her previous state, at which point she regains all of her powers.

Spellcasting. The Queen is an 20th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 24, +16 to hit with spell attacks). The Queen has the following Warlock spells prepared and can use any of her spells at or below 5th level at 5th level up to 5 times:

Cantrips (at will): Eldritch Blast, prestidigitation, ray of frost, Minor Illusion

1st level: Armor of Agathys, Hex, Hellish Rebuke, Charm Person, Ice Knife, Fog Cloud, 

2nd level: Enthrall, Hold Person, Misty Step, [Tooltip Not Found]

3rd level: Counterspell, Hypnotic Pattern, Tidal Wave

4th level: blight, Ice Storm, Banishment, 

5th level: Cone of Cold, scrying, Dominate Person, scrying, 

6th level (1 Slot): Mass Suggestion, Eyebite, Investiture of Ice

7th level (1 slot): [Tooltip Not Found], Etherealness

8th level (1 slot): dominate monster, Feeblemind

9th level (1 slot): Foresight

Chilling Touch. Melee Spell Attack: +16 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 paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Blade of Water. Melee Spell Attack: +16 to hit, reach 5 ft., one creature. Hit: 28 (4d8+8) cold damage. (Multi-attack with this weapon).

The lich 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 lich regains spent legendary actions at the start of its turn.

Cantrip. The Queen casts a Cantrip.

Enchanting Presence (Costs 2 Actions). The Queen fixes her Presence on all creatures it can see within 10 feet of it. The target must succeed on a DC 18 Wisdom saving throw against this magic or become frightened or Charmedfor 1 minute. The 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 lich's gaze for the next 24 hours.

Counterspell (Costs 3 Actions). The Queen can use Counterspell at 6th level whenever she chooses without the cost of a spell slot.

Restore Magic (Costs 3 Actions x2). The Queen can use Restore Magic 1 time per long rest. This is the equivalent of the Warlock capstone, but it takes all 3 legendary actions for that turn and the next turn as well. She regains her spell slots at the end of her following turn. She can only do this while within water.