North Called Sorcery

They were stuck in a Blizzard. They were attacked by a being of ice. Their family had a long story with Ice magic. The circumstances in wich those sorcerers died allow Winter itself to take over their heart. They now live again, feeling powerfull winter magic in them, and hearing a force calling them from an unknow land in the North.

Level 3: Frozen Hearth

Your own heart turned into ice, giving you the following benefits :

• Your hearth always know which way is north.
• You have advantage on saving throw against being charmed.
• You have the Armor of Agathys spell prepared. It counts as a sorcerer spell for you, and it doesn't count against your number of spells knows. You can cast it as a 1st level spell without expanding a spell slot. Once you cast it this way, you cannot do so until you finish a long rest.

Level 3: Solid Bastion

As a bonus action, you freeze the base of your body to stabilise yourself, creating a Solid Bastion. While in the Solid Bastion, you gain the following benefits :

• Your weight double, your speed become zero, and forced movement is halved. You can still teleport.
• You have advantage on strenght, constitution saving throw, but disadvantage on dexterity saving throw.
• You gain a bonus to AC equal to half your charisma modifier (rounded down)
• You have advantage on spell attack roll.
• When you deal cold damage, the damage increase by your charisma modifier.

The Solid Bastion has 3 times your sorcerer levels in HP and an AC equal to your charisma score. It is immune to cold, poison and psychique damage, and is vulnerable to fire damage. The bastion break once it reach zero HP or you use an action to exit it. Once you use this feature, you can't use it again until you finish a long rest, unless you expand a spell slot to do so.

Level 6: Bitter cold

Once per round, when you hit a creature with a spell attack that deal cold damage, one creature that failed their saving throw against one of your spell that deal cold damage, or take damage because of your armor of agathys, the creature see their speed halved and their AC and Dexterity saving throws reduced by two until the end of your next turn.

Level 6: Cold affinity

You gain resistance to Cold damage, and you ignore Cold damage Resistance.

In adition, you can use the Transmuted Spell Metamagic option a number of times equal to your proficiency bonus without expending a sorcery point if you change the damage type into Cold damage. You regain all expended uses of this features at the end of a long rest.

Level 14: White Castle

 You became more confortable with your bastion. Each time you enter your Solid Bastion, you gain one of the following benefits while in it :

• You create a 20ft radius lightly obscured area centered on you. Creatures affected by your Bitter cold are now afraid of you. If a creatures hit you or any allies within the area, the damage is reduced by your Charisma modifier.
• You now add your full charisma modifier to AC and are immuned to Cold damage and the charmed condition. When you enter your bastion, you gain the benefits of an Armor of Aghatys spell cast at a level equal to your Charisma modifier.
• You gain a flying speed equal to your walking speed, and you can break the Bastion as a bonus action.

Level 18: Subzero

While in your solid bastion, you are under all 3 benefits of the White Castle feature.