The Ice Blooded

From publisher blurb: The Ice Blood sorcerous origin provides a player with a depth of features themed around cold magic. Your cold spells gain amplified damage. Your body becomes resistant to the element it harbors so naturally. Eventually, you gain the ability to learn cold magic beyond your normal capacity. Finally, you gain total mastery of the frost energy you harbor and can even channel it’s overflow towards those around you. This is a guide to an alternative sorcerous origin option for the Sorcerer class of Dungeons and Dragons (5e).