Frostjack

Chilling Presence. At the start of each of its turns each creature within 15 ft. of it: 5 (2d4) cold (DC 16 Con negates). For each min a creature spends within 15 ft. of it: suffer one level of exhaustion from cold exposure (DC 16 Con negates). Unprotected nonmagical flames within 15 ft. of it are extinguished. Any spells of 3rd level or lower that provide resistance to cold and that are within 15 ft. of it immediately end. Water freezes if it remains within 15 ft. of it for at least 1 min.

Ice Walk. Move across and climb icy surfaces with o ability check. Difficult terrain composed of ice or snow doesn't cost it extra move.

Magic Resistance. Advantage: spell/magic effect saves.

Multiattack. Two Ice Blade attacks and one Winter's Touch attack.

Ice Blade. Melee Weapon Attack: +8 to hit, 5 ft., one target, 8 (1d8+4) piercing damage + 14 (4d6) cold.

Winter's Touch. Melee Weapon Attack: +8 to hit, 5 ft., one target, 6 (1d4+4) slashing damage + 7 (2d6) cold and target must make a DC 15 Con save. Fail: creature begins to freeze and has disadvantage on weapon attack rolls or ability checks that use Str or Dex. It must re-save at end of its next turn becoming incapacitated and unable to move or speak as it freezes solid on a failure or ending effect on success. Creature remains frozen until it spends 12+ hrs in a warm area thawing out or until it takes at least 10 fire.

Icicle Barrage (Recharge 5-6). Icicles fly from its hand in 30' cone. Each creature in area: 17 (5d6) piercing damage and 17 (5d6) cold (DC 16 Dex half).

Hoarfrost Warding (3/Day). When it takes fire it gains resistance to fire including triggering attack until end of its next turn.