Cresseida, Winter's Successor

Keen Awareness. Cresseida has an acute awareness of danger after her time in Frostime; she can't be surprised while she is conscious, and other creatures don't gain advantage against her as a result of not being seen by her. 

Magic Resistance. The maiden has advantage on saving throws against spells or other magical effects. 

Spellcasting. Skylla is an 11th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 20, +12 to hit with spell attacks). Skylla has the following spells prepared:
Cantrips (at will): Chill Touch, Druidcraft, Eldritch Blast, Frostbite, Guidance, Ray of Frost. 
2 / Day: Armor of Agathys, Bane, Counterspell (up to 5th-level), Cure Wounds (up to 5th-level), Ice Knife, Inflict Wounds, Rime's Binding Ice, 
1 / Day: Compulsion, Cone of Cold, Contagion, Dispel Magic, Dominate Person, Fear, Synaptic Static. 

Multiattack. Cresseida may make Three Eldritch Blast attacks or she may cast a leveled spell as her action, followed by a cantrip as her bonus action. 

Eldritch Blast. Ranged Weapon Attack: (+12) to hit, range 120ft., one target, three beams. Hit: (1d10 + 6) force damage.

Freezing Stare. Cresseida targets one creature she can see within 60ft of her. That target must succeed on a DC 20 Constitution Saving Throw or take (8d6) cold damage and become paralyzed until the end of her next turn. If the creature succeeds this saving throw they take half damage and are not paralyzed. A success against Freezing Stare makes that creature immune to its effect for 24 hours. 

Fey Step. As a bonus action, Cresseida can magically teleport up to 30 feet into a space where she can see, snowflakes and icicles sprouting from the ground she touches. One creature that she can see within that range must succeed on a DC 20 Wisdom Saving Throw or be frightened, their speed becoming 0, until the end of her next turn. A creature that succeeds on this saving throw is unaffected. 

Frigid Rebuke. In response to taking damage from a creature Cresseida can see within 60ft of her, she can force that creature to succeed on a DC 20 Constitution Saving Throw or have them take (2d10) cold damage. A creature that succeeds on this Saving Throw is unaffected. 

Beguiling Defenses. Cresseida is immune to being charmed, and when a creature attempts to charm her, she may use her reaction to turn that charm against the opposing creature, unless they succeed on a DC 20 Wisdom Saving Throw, for 1 minute or until that creature takes damage.