Draugr Frostbringer

Medium undead, any evil alignment
AC: 15 (Armor Scraps) HP: 102 (12d8 + 48) Speed: 30 ft.
STR 16(+3) DEX 14(+2) CON 18(+4) INT 6(-2) WIS 12(+1) CHA 12(+1)
Saving Throws: Constitution +7, Charisma +4
Damage Vulnerabilities: Bludgeoning, Fire
Damage Resistances: Necrotic
Damage Immunities: Cold, Poison
Condition Immunities: Charmed, Exhaustion, Poisoned
Senses: Darkvision 60 ft., Passive Perception 11
Languages: understands the languages it knew in life but can’t speak
CR: 6   Aura of Winter: The draugr frostbringer carries the frost of the Black Winter’s Cold, radiating around it for 30 feet radius. Additionally, the draugr frostbringer deals (1d10) cold damage to the creatures that are within 30 feet of it at the start of its turn. The creatures also have their speed reduced by 10 feet while within the aura.
Ice Walker: The draugr can walk on ice without any penalties.
Ice Burst: When reduced to 0 hit points, draugr frostbringer explodes into many shards of ice. Any creature that is caught within 10 feet of it must succeed on a DC 15 Dexterity saving throw or take (6d4) cold plus (6d4) piercing damage on a failed save, taking half as much on a successful save.
ACTIONS Multiattack: The draugr frostbringer makes two greataxe attacks.
Frostbitten Great Axe: Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: (2d6 + 3) slashing damage plus (2d8) cold damage.   Ice Shards (1d4 shards): Ranged Attack: +5 to hit, range 30/60 ft., multiple targets. Hit: (2d4) piercing damage plus (2d4) cold damage, and the targets’ speeds are reduced by 10 feet until the start of their next turn.
Mark of Frost: The draugr frostbringer targets an undead within 30 feet of it. The creature gains the Ice Burst feature, and gains (1d4) cold damage on its attacks.
Loot:

• Frostbitten Great Axe 
• Hel Shoes only if in Helheim!

The draugr frostbringer carry the Black Winter with them wherever they go. They are the omen of dark days ahead. They can freeze those around them slowly, and raise frostbitten dead from the corpses of freshly slain. It is not unlikely to see draugrs band together with Hel's spring, as both creatures are servants of Hel. Yet, unlike other draugrs, draugr frostbringers do not conjoin with Hel's spring. Those who observe the undead say that this is because they are rather the servants of Odd and not Hel. In any case, they share the promise of death with hordes of Helheim.

Black Winter's Cold

• The cold spreading from the Black Winter is an unnatural, harsher cold even for the north. In addition to the fact that it carries the effects of extreme cold, Black Winter's Cold cause the following effects:

1. If you have resistance to cold, it drops to normal, and normal drops to vulnerability.
2. When you are subjected to Black Winter’s Cold, you must make a DC 15 Constitution saving throw or take one level of exhaustion immediately. Then you continue to take additional levels of exhaustion if you fail your saves at the end of each hour you spent within the cold.
3. Even while wearing cold weather gear, you must make a DC 10 Constitution saving throw at the end of each hour spent in this cold or take one level of exhaustion.