Your Strength score increases by 1, and your Charisma score increases by 2.

Thanks to your infernal heritage, you have superior vision in dark and dim conditions. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

You have resistance to fire damage.

You can speak, read, and write Common and Infernal.

You know the Vicious Mockery Cantrip.  Charisma is your spellcasting ability for it.

Starting at 3rd level, you can use your action to unleash devilish energy within yourself, causing you to take a full devil form.

Your transformation lasts 1 minute or until you end it as a bonus action.  During it, at the start of each of your turns, you regain hp equal to half your level rounded up, and once on each of your turns, you deal extra necrotic damage equal to your level on one target when you deal damage to it with an attack or spell.

If you are knocked unconscious while this ability is active, you do not regain health at the beginning of your turn until you regain consciousness, if you have any remaining time.

After you use this feature, you cannot use it again until after you finish a long rest.