Bad Santa

Aura of False Goodness. Bad Santa emanates in Aura in a 30-foot Emanation while he doesn’t have the Incapacitated condition. Wisdom Saving Throw: DC 21, each creature that starts its turn in the aura. Failure: The target has the Charmed condition, and repeats the save at the end of each of its turns, ending the effect on itself on a success. After 10 minutes, it succeeds automatically. While Charmed in this way, the target has the Poisoned condition. Success: The target is immune to this Bad Santa's aura for 24 hours.

Legendary Resistance (3/Day). If Bad Santa fails a saving throw, he can choose to succeed instead. 

Magic Resistance. Bad Santa has Advantage on saving throws against spells and other magical effects.

Multiattack. Bad Santa makes three attacks, using Arcane Sword or Cold Ray in any combination. He can replace one attack with a use of (A) Punish the Naughty if available or (B) Spellcasting.

Arcane Sword. Melee Attack Roll: +12, reach 5 ft. Hit: 17 (2d10 + 6) Slashing damage plus 11 (2d10) Force damage, and the target has the Prone condition.

Cold Ray. Ranged Attack Roll: +13, range 120 ft. Hit: 21 (6d6) Cold damage. Until the end of the target's next turn, its Speed is reduced by 10 feet, and it has Disadvantage on attack rolls.

Punish the Naughty (Recharge 5-6). Each creature in a 45-foot cone suffers one of the following effects (Bad Santa's choice):

Icicle Burst. Constitution Saving Throw: DC 21. Failure: 18 (4d8) Piercing damage plus 14 (4d6) Cold damage, and the target has the Restrained condition for 1 minute. The target or another creature within 5 feet can use an action to break the icicles.
Lumps of Coal. Dexterity Saving Throw: DC 21. Failure: 18 (4d8) Bludgeoning damage plus 14 (4d6) Fire damage, and the target starts burning.

Success: Half damage only.

Spellcasting. Bad Santa casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 21):

At Will: Detect Thoughts, Elementalism, Fog Cloud, Knock, Minor Illusion, Protection from Evil and Good
3/Day Each: Animate Objects, Haste, Wall of Ice

Glacial Teleport. Bad Santa teleports up to 60 feet to an unoccupied space he can see. Each creature of Bad Santa's choice within 20 feet of his destination space suffers the following effect. Constitution Saving Throw: DC 21. Failure: The target has Vulnerability to Cold damage until the start of Bad Santa's next turn.

Frigid Rebuke. Trigger: Bad Santa takes damage from a creature he can see within 60 feet. Response–Constitution Saving Throw: DC 21, the triggering creature. Failure: 11 (2d10) Cold damage. Success: Half damage.

Parry. Trigger: Bad Santa is hit by a melee attack roll while holding a weapon. Response: Bad Santa adds 5 to his AC against that attack, possibly causing it to miss.

Legendary Action Uses: 3. Immediately after another creature’s turn, Bad Santa can expend a use to take one of the following actions. Bad Santa regains all expended uses at the start of each of his turns.

Charge. Bad Santa moves up to his Speed and makes one Concussive Hammer or Cold Ray attack.

Polar Vortex. Bad Santa casts Ice Storm, using the same spellcasting ability as Spellcasting. Bad Santa can't take this action again until the start of his next turn.