Revenant

A Raider Captain stalks his prey through the barrens of the tundra, wolf at his side. The wind kicks up shimmering plumes of frost; he doesn't see the frozen bolt hurtling towards him. It strikes with a deafening crack; the wolf is down. The Captain flees for cover, but it's too late — he is frozen in a crystalline prison.

His battle cry freezes in his throat; there is only deafening silence. He sees a shadow approaching, cloaked in the ice and whirling snow, but it vanishes as quickly as it appeared. Fear grips him as he scans the white wastes.

A second bolt pierces the ice shelf. Biting whirlwinds erupt and tear at his frozen body. He catches a glimpse of the shadow in the squall, crossbow in hand. The hunt has ended; he shatters in the wind.

Level 3: Emanation of Winter

You gain the following benefits.

Biting Cold. Damage from your weapon attacks, Ranger spells, and Ranger features ignores Resistance to Cold damage.

Frost Resistance. You have Resistance to Cold damage.

Polar Emanation. When you cast hunters mark you can instead cast a 15-foot Emanation for up to 10 minutes, with concentration. Until the spell ends, any attack you make deals an extra 1d6 Cold damage when you hit a creature in the Emanation. In addition, the ground in the Emanation is Difficult Terrain for your enemies.

This damage increases to 2d6 at level 7, and 2d8 at level 11. Using a level 5 spell slot to cast increases the damage by an additional d8.

Additionally this spell takes on any class buff granted to hunters mark in its own way;
Level 13: Relentless Hunter. Taking damage can't break your Concentration on Polar Emanation.
Level 17: Precise Hunter.  You have Advantage on your first attack roll on a creature standing within your Emanation per turn.
Level 20: Foe Slayer. Your Polar Emanations damage increases to d10s as opposed to d8s

Level 3: Armour of Frost

When you deal damage to a target with cold damage or reduce a creature to 0 hit points with an attack while not wearing heavy armour, you gain one layer of Frost Armor. You can have a maximum number of layers equal to your Proficiency Bonus. Your layers last for 1 minute, or until you take a short or long rest. 
Mechanics & Benefits
AC Bonus: Every even numbered stack grants a +1 to AC.
Damage Reduction: Whenever you take bludgeoning, piercing, or slashing damage, the damage is reduced by an amount equal to the number of Frost Armor layers you currently have.
Losing Layers: Every time you take damage from an attack, you lose 1 layer of Frost Armor after the damage is resolved.
Maximum Stacks Benefit: If you are at your maximum allowed layers of Frost Armor, you also gain resistance to bludgeoning, piercing, and slashing damage.

Level 7: Shield of the Winters Wrath

At level 7 you improve your defensive capabilities, you can now cast the shield spell. 

• Reaction, which you take when you are hit by an attack roll or targeted by the Magic Missile spell. An imperceptible barrier of magical force protects you. Until the start of your next turn, you have a +5 bonus to AC, including against the triggering attack, and you take no damage from Magic Missile.
• Additionally, if cast within one of your emanations, you may heal an amount equal to your proficiency bonus.

You can cast this spell without expending a spell slot a number of times equal to your Wisdom modifier (minimum of once), and you regain all expended uses when you finish a Long Rest.

Level 11: Behemoths Rebuke

When a creature hits you with an attack roll, you can take a Reaction to force the creature to make a Wisdom saving throw against your spell save DC. On a failed save, the target has the Stunned condition until the end of your next turn. While the target is Stunned, its Speed is reduced to 0 feet.

You can use this feature a number of times equal to your Wisdom modifier (minimum of once), and you regain all expended uses when you finish a Long Rest.

Level 15: Emanation; Blizzard

Once per short-rest, freeze a massive area, slowing and eventually stunning all enemies inside. While buffing allies inside the radius.
As an action you hurl a cryo-grenade to a point within 30 feet. A 30-foot-radius sphere centered on that point becomes difficult terrain for 3 turns. Any enemy that starts its turn in the area must make a Constitution saving throw.
Enemies
• Failed Save: Takes 4d6 cold damage and is Restrained.
• Successful Save: Takes half damage and is slowed by half their speed.
• If a creature fails its save two turns in a row while inside the blizzard, it becomes Paralyzed (Frozen) for 1 minute or until it takes fire damage.
Allies
• Heal for 1d4 plus your constitution modifier immediately and at the start of their turn if still in the radius.
• Have their move speed increased by 5 feet.