Cinninmus Frostflourish

Fey Step (recharge 4-6) As a bonus action, Cinninmus can teleport up to 60 ft to an unoccupied space she can see.

Innate Spellcasting. Cinninmus' innate spellcasting ability is Wisdom (Spell save DC 21). She can innately cast the following spells without material components.

At Will: charm person, calm person, summon beast, silence 

3/day: faerie fire, summon fey, winter sentinel, ice beam

1/day: wrath of nature, conjure fey, dominate monster

Spellcasting. Cinninmus is a 9th level spellcaster and has the following spells prepared:

Cantrips (at will): frostbite, ray of frost, chill touch, toll the dead, primal savagery 

1st level (4 slots):  bane, armor of agathys, chromatic orb, ensnaring strike, hunter's mark, zephyr's strike 

2nd level (3 slots): hold person, winter sentinel, moonbeam, rime's binding ice

3rd level (3 slots): ice beam, counterspell, dispel magic, fear, slow, sleet storm, wall of water

4th level (3 slots): guardian of nature, death ward, dominate beast, ice storm

5th level (3 slots): circle of power, cone of cold, hold monster, maelstrom 

Relentless Chill. Cinninmus ignores resistance to cold damage.

Perfection 3/day. If Cinninmus misses with an attack or spell, she can choose to hit instead.

Monochromatic Magnificence (recharges on a short or long rest) If Cinninmus is reduced to 0 hit points and she is within the fey realm, frigid winds sweep through the air, healing her for 50 hit points. The winds are so cold, all creatures within 120 ft radius must make a DC 21 Constitution saving throw. On a failure, they take 12d6 cold damage, on a success, they take half damage.

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

Legendary Resistance 3/day. If Cinninmus fails a saving throw, she can instead choose to succeed.

Hypothermic Cut (recharges 5-6). As part of the attack action, on a hit Cinninmus can cause her blade to become serrated with hundreds of tiny icicles. A creature takes an extra 4d10 cold damage and must make a DC 21 Constitution saving throw. On a failure, the wound begins to freeze rapidly, and at the start of each of their turns they take an addition 1d10 cold damage. On a success, they take half as much damage and their wound does not freeze. A creature can repeat the saving throw at the end of each of its turns, ending the effect on a success.

Multiattack. Cinninmus makes two attacks with Melancholia

Melancholia. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 14 (2d8 + 5) slashing damage plus 12 (3d6) cold damage. 

Parry. Cinninmus adds 3 to her AC against 1 melee attack that would hit her. To do so, she must see the attacker and be wielding a melee weapon. 

Cinninmus can take 3 legendary actions, choosing from the options below. Only one legendary option can be used at a time and only at the end of another creature's turn. Cinninmus regains all spent legendary actions at the start of her turn.

Cantrip (1 action). Cinninmus casts one cantrip.

Spell (2 actions). Cinninmus casts one of her prepared spells.

Melancholia Strike (2 actions). Cinninmus makes one attack with Melancholia.

Teleport (2 actions). Cinninmus can teleport to an unoccupied space within 60 ft of her.