Base Class: Sorcerer
You cast magic by sheer force of will.
Constitution Casting
You are a Constitution based caster, this means you can continue to cast magic after you have expended all spell slots and sorcery points at the expense of your Hit Points. Subtract the number of hit points equal to the level of spell you wish to cast for every spell you cast in this way until you reach 10 Hit Points or fewer, at which time you must take a short or long rest before you can continue to cast spells in this way. Example, for a fourth level spell you must subtract four Hit Points from your total Hit Points Maximum, Temporary Hit Points CANNOT be used for this.
Harder to Kill
Your hit point maximum increases by 2 and increases by 2 again whenever you gain a level in this class.
Resilient
Parts of your skin are now covered by a thin layer of dark, shadowy energy. When you aren’t wearing armor, your AC equals 13 + twice your Dexterity modifier and you have gained resistance to radiant damage.
Devilish Sight
Starting at 14th level you have darkvision out to 60 ft. If you already have darkvision, it stacks. You can see in both magical and nonmagical darkness.
Shadow Form
Starting at 18th level, you can spend 6 sorcery points as a bonus action to magically transform yourself into a shadowy form. In this form, you have resistance to all damage except force and radiant damage, and you can move through other creatures and objects as if they were difficult terrain. You take 5 force damage if you end your turn inside an object.
You remain in this form for 1 minute. It ends early if you are incapacitated, if you die, or if you dismiss it as a bonus action.