Auroraborn

Your soul is infused with the beautiful cruelty of the far north, home of the mysterious aurora.  This magical light that fills the frigid night skies at certain times of the year also fills your heart and mind, granting you a mysterious but powerful control over innate magics, particularly those dealing with light and ice.  Perhaps you were exposed to the aurora's light on an expedition, or perhaps you hail from a northern continent, where the aurora is a commonly celebrated phenomenon.  Were you born under its colorful glow, or did you discover its beauty later in life?  Whatever the case, growing in this class means fostering the beauty and danger of the frigid northern wilds within yourself.

Aurora's Light

Starting at 1st level, your inner light allows your sight to pierce the darkness.  You gain darkvision out to a range of 60 feet, or increase the range of your darkvision by 60 feet if you have it already.

You also know the dancing lights cantrip, which does not count against the number of cantrips you know.

Chill of the North

Starting at 1st level, your soul has been steeped in the frigid magic of the far north.  Whenever you cast a spell that deals cold damage to a target, you may reroll any number of the damage dice for that spell.  You may use this feature once, regaining expended uses after a long rest.  As you gain additional levels in this class, you gain additional uses of this ability:  2 uses at 5th level, 3 uses at 11th level, and 4 uses at 17th level.

Armor of Frost

At 6th level, you have begun to embody the primordial frosts of the northern tundra.  You gain resistance to cold damage. 

In addition, whenever you finish a long or short rest, frost suffuses your skin, granting you temporary hit points equal to your sorcerer level.  Until these temporary hit points are depleted, you are also granted a +2 bonus to your AC, as your body is protected by a layer of frost.

Grip of Winter

Starting at 14th level, you are able to call upon primordial ice to slow and ensnare your enemies.  As an action you may force a number of creatures equal to your Charisma modifier (minimum one) to make a Constitution saving throw against your spell save DC.  Targets must be visible and within 60 feet of you.  On a failed saving throw, a target's movement speed is reduced to 0 until the beginning of your next turn.  On a success, the creature's movement speed is reduced by half instead.  You may use this feature once, regaining the ability to do so after a long rest.

Grand Aurora

At 18th level, the light of the aurora has found its home within your soul.  You gain immunity to cold damage, and resistance against radiant damage.

In addition, whenever a creature fails a saving throw against the effects of one of your spells that deals cold damage, you may expend 2 sorcery points to inflict one of the following effects on that creature, in addition to the effects of the spell:

Freeze.  The target is inundated with ice, taking an additional 2d12 cold damage from the spell.

Glaciate.  The target is covered in rime, granting it disadvantage on the next attack roll, ability check, or saving throw it makes within one minute.

Dazzle.  The target is dazzled by the aurora's light, and is blinded until the end of your next turn.