Reindeerkeeper

You are bonded to the group of creatures which actually carry Christmas on their back. Once they were mythology, now they are part of every Christmas night, pulling the big sleigh with the presents through the sky. Feed them well, and they thank you.

Favoured Enemy

When you choose this archetype at 3rd level, all creatures of Naughty alignment become your favoured enemy.

Friend's Guidance

Starting at 3rd level, when an ally makes a Dexterity or Constitution saving throw, you can choose to lend them a helping hand and roll for them instead, but they have to take your roll.

Surprises For You

There is nothing quite as surprising as wild magic. And there is nothing quite like a delightful surprise on Christmas. At 7th level, you can imbue your weapon with wild magic that changes the type of damage your weapon causes based on the table below (roll 1d10), and increases it's damage by 2d8 for two rounds.

1. Acid
2. Cold
3. Fire
4. Force
5. Lightning
6. Necrotic
7. Poison
8. Psychic
9. Radiant
10. Thunder

The extra damage it causes increases at 10th, 13th, 16, and 19th level by 1d8. You can you this ability once per long rest.

Reindeer Whisperer

At 11th level, you have proven your friendship with the majestic arcane reindeer of Santa, who you now only need to call for aid. Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen, and Rudolph can be summoned by will and take the Charge action twice during an encounter. You can take this action once per long rest.

• Dasher: Slashing Damage
• Dancer: Cold Damage
• Prancer: Slashing Damage
• Vixen: Fire Damage
• Comet: Force Damage
• Cupid: Necrotic Damage
• Donner: Thunder Damage
• Blitzen: Lightning Damage
• Rudolph: Radiant Damage

Reindeer of Santa (Medium magical beast, varying alignments) 
AC: 14, HP: 4d8+5, Speed: 40ft/40ft flying, Passive Perception: 14
STR: 14(+2) DEX: 16(+3) CON: 12(+1) INT: 6(-2) WIS: 14(+2) CHA: 10(0)
Damage Vulnerabilities: poison, thunder, lightning
Damage Resistances: psychic
Condition Immunities: charmed
Languages: Understands but does not speak Common
Best Buddy: In a fight, whichever reindeer you summon will stand by your side and sweep you off the ground should you be in trouble. This will happen more or less automatically as a reaction.
Actions
Charge: If the flying arcane reindeer moves at least 20ft straight towards a target and then hits it with a ram attack on the same turn, the target is then trampled over, taking damage from the hooves along with the reindeer's damage type. The creature must succeed on a DC 17 Strength saving throw or be knocked prone. Charge: Melee Weapon. Attack: +7 to hit, Reach: 60ft, one target. Hit: 5d8+5 damage, or half that if the target succeeds on their saving throw

Polar Express

After reaching the 15th level, the friendship mentioned above grows into an undeniable bond that grants you the power to leave your troubles miles away. As two actions that you need to concentrate on, you can summon a splendidly decorated sleigh, loaded with gifts, that is 20ft long, 10ft wide, and 10ft tall. The sleigh is pulled by the aforementioned magical reindeer and has a walking speed of 80ft and a flying speed of 150ft.

The sleigh illuminates a 10ft radius around itself, with dim light extending 10ft beyond that. The sledge and its reindeer are your property, immune to all damage and magical effects outside those created by a wish spell. It will always be recognised by those who believe in the magic of Christmas.

The sleigh can only be driven by you, and driving it requires your concentration as if you were concentrating on a spell. If your concentration is broken while driving it, the sleigh will stand or hover in place, and you must use your action to begin driving it again. It can carry up to 5 other Medium sized passengers. While you drive the sledge, creatures riding in it gain the automatic benefit of your Friend's Guidance feature.

The sleigh will remain with you for up to 1 hour, or until you dismiss  it as an action. After this time, you and any passengers still in the sleigh will be ejected, floating harmlessly to the ground if you were airborne, and the sleigh will vanish.

The sleigh can only be summoned once per long rest.