Ice Walk. Zahasshi can move across and climb icy surfaces without needing to make an ability check. Additionally, difficult terrain composed of ice or snow doesn't cost her extra movement.

Undead Nature. Zahasshi doesn’t require air, sustenance, or sleep.

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

Legendary Resistance (3/Day). If Zahasshi fails a saving throw, she can choose to succeed instead.

Spellcasting. Zahasshi is an 11th-level spellcaster. Her spellcasting ability is Charisma (spell save DC 15, +7 to hit with spell attacks). Zahasshi has the following Wizard spells prepared:

Cantrip (At will): Ray of Frost, Chill Touch, Message, Blade Ward, Frostbite

First Level (6 Slots): Chromatic Orb, Armor of Agathys, Ice Knife, Frost Fingers

Second Level (5 Slots): Rime's Binding Ice, Snilloc's Snowball Swarm, Dragon's Breath

Third Level (4 Slots): Summon Shadowspawn, Spirit Shroud, Counterspell

Fourth Level (3 Slots): Ice Storm, Coujure Minor Elemental, Elemental Bane

Fifth Level (2 Slots): Cone of Cold, Summon Draconic Spirit

Sixth Level (1 Slot): Wall of Ice

Multiattack. Zahasshi can use her Frightful Presence. She then makes three attacks: one with her bite and two with her claws.

Bite. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 19 (3d10 + 7) piercing damage plus 9 (3d6) cold damage.

Claw. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 16 (3d8 + 7) slashing damage.

Tail. Melee Weapon Attack: +12 to hit, reach 15 ft., one target. Hit: 16 (4d6 + 7) bludgeoning damage, if the creature is large or smaller, it must make a DC 18 Dexterity save, or be knocked prone.

Frightful Presence. Each creature of Zahasshi's choice that is within 120 feet of Zahasshi and aware of her must succeed on a DC 15 Wisdom saving throw or become frightened 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 Zahasshi's Frightful Presence for the next 24 hours.

Cold Breath (Recharge 5–6). Zahasshi exhales an icy blast in a 60-foot cone. Each creature in that area must make a DC 19 Constitution saving throw, taking 52 (13d8) cold damage on a failed save, or half as much damage on a successful one.

Zahasshi 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. Zahasshi regains spent legendary actions at the start of her turn.

Detect. Zahasshi makes a Wisdom (Perception) check.

Tail Attack. Zahasshi makes a tail attack.

Wing Attack (Costs 2 Actions). Zahasshi beats her wings. Each creature within 10 feet of Zahasshi must succeed on a DC 19 Dexterity saving throw or take 13 (2d6 + 6) bludgeoning damage and be knocked prone. Zahasshi can then fly up to half her flying speed.

Ice Spikes (Costs 2 Actions). Zahasshi uses her Ice Magic to raise Ice Spikes from the ground to three different targets. Targeted creatures must succeed on a DC 16 Dexterity saving throw or take 32 (8d8) Piercing Damage on a fail and half on a success.