Frozen Soul

Your innate magic commands the element of ice, and stems from the blizzard contained within your soul. Perhaps you were touched by the essence of the para-elemental plane of ice as a child, or you descended from one of Auril's chosen. Perhaps you were granted a mote of power from the Goddess herself. Whatever the source, this power both dangerous and beautiful, has manifested within you.
This legacy may make itself known in multiple ways both physical and emotional. Your skin might be unnaturally cold, the air around you carrying a bitter chill, your mind might be cool and calculating finding it hard to understand the rampant emotions of others.
Your power is born from the ancient power in the frozen winterscapes of the world. Whether it was a secret of the frozen tundra, a spirit of nature, a mark from a powerful dragon, or any number of sources, your blood runs cold. Your skin is cold to the touch, and you don’t seem to mind when the temperature drops outside. You’re naturally more comfortable deep in the frozen wilderness, which will usually lead you to a more solitary lifestyle. 

Frozen Heart

When you breathe, you can see your breath even in humid and high temperature atmospheres.

At 1st level, frozen environments, such as snow, mountains, and ice, do not count as difficult terrain for you or your party. You also gain resistance to cold damage.  At 1st level, You can also speak, read, and write Primordial. (Knowing this language allows you to understand and be understood by those who speak its dialects: Aquan, Auran, Ignan, and Terran).  The arcane magic you command is infused with elemental ice. As the magic flows through your body, you discover you can create layers of frost upon your skin. While you are not wearing armor, your AC equals 10 + your Dexterity modifier + your Charisma modifier.

Crystalize:  When you reach 3rd level in this class, you learn how to further strengthen your defenses. As a bonus action, you can expand 1 sorcery point to add your Constitution modifier to your Armor Class if you aren’t wearing armor or wielding a shield, and your skin assumes a cold, icy blue appearance. This effect lasts until you end it as a bonus action, you are incapacitated, or you don armor other than a shield.

Cold Decision

At 6th level you can choose one of these abilities to be active per Long Rest.

Relentless Cold
If you are reduced to 0 hit points, you can use your reaction to draw on the winds of Winter to stave off death. You are instead reduced to 1 hit point, and each creature within 10 feet of you takes cold damage equal to your Charisma modifier and, if the creature is Large or smaller, is pushed back 10 feet. If you use this feature while under the effects of your Mantle of Ice, this feature instead deals cold damage equal to double your Charisma modifier, and pushes foes back 20 feet. Then your Relentless Cold immediately ends.  Once you use this feature, you can’t use it again until you finish a long rest.

OR

Frostbite
The cold sets in, You add a damage bonus equal your Charisma modifier to any spell you cast that deals cold damage

Arctic Soul

At level 14, the cold inside of you changes your body. You can gain the benefits of a Long Rest by taking a Short Rest instead. If you do not have it from your chosen race, you gain darkvision out to 60 feet.

In addition, your spells ignore resistance to cold damage.

Ice Storm

For the next 1 round per sorcery point spent, as an action you can create 10ft radius sphere of swirling arctic wind around you per sorcery point spent, 20ft for 2 points etc... any creature that enters or starts its turn within this radius other than you must make a constitution saving throw or take 8d6 cold damage on a failed saving throw or half on a successful one. The area acts as difficult terrain for everyone but you. Creatures also have disadvantage on saving throws against spells dealing cold damage. You can your end your Ice Storm prematurely as an action.
You can use this action once per long rest.