Etherheart

You were not born with power. You were not meant to have power. Yet, somehow, power has found its way to you. You can now produce your own artificial source of magical power. Every minute of every day, you can feel it—and see it— running through your veins. Your heart now beats with the power of magic, an amazing feat of magical science. However, such power comes at a cost. Specifically, a toll on your body.

Artificial Magic

Immediately after you cast a sorcerer spell of 1st level or higher, the DM can have you roll a d20. If you roll a 1, roll on the Artificial Magic Mishap table to create a random magical effect.

Sacrificial Spell

Starting at 1st level, whenever you cast a spell that does damage, you can spend up to 6 hit points (temporary hit points do not count) to do an additional 1d6 psychic damage—to an affected creature you chose—for every 2 hit points spent.

At 6th level, the damage die becomes d8, at 12th level, it is d10 and at 18th level, it is d12.

Ethereal Shield

Starting at 6th level, every time you gain a level (including 6th level) as a Sorcerer, you can increase your maximum Hit Points equal to your Charisma modifier divided by 2 (rounded down, minimum of 1).

Additionally, you can now use your flow of arcane power to protect yourself from harm. As a reaction, you can cause the energy in your veins to leap out and shield you from an incoming attack. Roll 3d8 and add the total to your temporary hit points until the start of your next turn. You can do this a number of times equal to your Charisma modifier (minimum of 1).

At 12th level, the die becomes d10, and at 18th level, it is d12.

Siphon Ether

 As an action, you may spend 5 sorcery points in order to target a living, magical creature within 40ft. That creature must make a Constitution saving throw. When target fails it's save, arcane energy releases from its skin and flows through the air to you, where it's absorbed through your skin. Target takes 3d6 psychic damage, and you gain hit points equal to half the amount of psychic damage dealt. Your Hit Point maximum is also increased equal to the amount of Hit Points that were gained with this ability. This temporary increase of maximum Hit Points lasts until your next long rest.

Arcane Absorption

At 18th level, immediately after a creature casts a spell that targets you or includes you in its area of effect, you can use your reaction to force the creature to make a saving throw with its spellcasting ability modifier. The DC equals your spell save DC. On a failed save, you negate the spell's effect against you, and you regain hit points equal to half of the spell’s damage. 

Once you use this feature, you can't use it again until you finish a long rest.