Base Class: Sorcerer
Your magic is created by pieces of the frozen lands. This power within you might have been passed down from ancestors who protected the frozen lands, or it might have been forced on you by an encounter with some enchanted ice. Regardless of the source of your power, you are cold incarnate.
Frozen Body
Starting at 1st level, your skin takes on a faintly ice-like, crystalline glow. Your hit point maximum increases by 1 and increases by 1 again whenever you gain a level in this class.
In addition, you're most comfortable in the ice and snow. You ignore difficult terrain caused by ice and snow, and when you walk on ice, you only spend 1 foot of movement for every 2 feet you move.
Create Ice
At 1st level, you can use a bonus action to turn up to 5 continuous 5-foot spaces on the ground into icy terrain, originating from the ground at your feet. The ice is difficult terrain and lasts until the end of your next turn.
You can spend up to 2 sorcery points when creating this terrain to increase the number of spaces you can target with this feature by 5 for each sorcery point spent.
Cold-hearted
At 6th level, you gain resistance to cold damage. When you deal cold damage to a Large or smaller creature with a spell, you can spend 1 or more sorcery points to attempt to freeze it in place. When you do, the creature's speed is reduced by 15 feet for each sorcery point you spend until the end of its next turn. If you reduce a creature's speed to 0 in this way, it takes 2d6 cold damage.
In addition, you can now use your Create Ice feature to freeze water as well as ground.
Flash Freeze
By 14th level, you're most confident on the ice. Your movements don't provoke opportunity attacks while you're walking on icy terrain.
In addition, when a creature within 5 feet of you that you can see hits you with an attack, you can use your reaction to release a blast of freezing cold, dealing cold damage to the attack equal to half your sorcerer level + your Charisma modifier. When you do, you can also create up to 5 continuous spaces of icy terrain, originating from the ground at your feet. This icy terrain lasts until the end of your next turn.
Frozen Essence
At 18th level, you gain immunity to cold damage and resistance to fire damage.
You also learn the wall of ice spell. The spell counts as a sorcerer spell for you, but doesn't count against the number of sorcerer spells you know. In addition, you can cast the spell once without expending a spell slot. When you do, the panels of ice created by the spell don't need to be continuous with one another. Once you cast the spell in this way, you can't do so again until you finish a long rest.