Tainted Demon Blood

Sorcerers of the Tainted Demon Blood or Demon Kin don't need to hide about the sorcerous origins but some do for those who is one probably has experienced something detrimental to have this power. There are those however that go out of their way to get this power by capturing a Demon or Devil. The only way to truly become Demon Kin is when the blood of the Demon or Devil mixes with yours, of course this would mean that you survived the encounter. Of course innately Devils aren't the type to start up a fight so usually Demon Kin are made from Demon hence the name. You also gain the Warlocks spells.

Demonic Resilience

Your blood has changed your appearance, either you've gotten horns or maybe you've grown a tail but one thing is for sure, you're different. Your skin is as tough as nails giving you a natural AC of 13+Dex and you gain resistance to Fire damage.

Demonic Tampering

Whenever you cast a spell of 1st level or higher you can use your reaction to cause a different creature within 60 ft to make a Constitution saving throw against your spell save and take half damage. You can do this up to a number of your charisma modifier.

Innate Spells

When you choose this subclass depending on your alignment you can gain 1 of 3 spells. For good aligned people you gain the Guiding Bolt spell, for Neutral aligned people you gain the Protection from Good and Evil spell, and for Evil aligned creatures you gain the Inflict Wounds spell.

Evil

You learn the Inflict Wounds spell.

Good

You learn the Guiding Bolt spell.

Neutral

You learn the Protection from Good and Evil spell.

Merciless Restoration

When you kill a creature you absorb part of their essence.  Anytime you kill a creature you can use a spell slot to regain a 2d6 hit points, increases by 1d6 for every spell level above 1st.

Underworld Wings

Through your experience as a Demon Kin your body has gone through another transformation. You can now create and dismiss wings which resemble that of black eagle wings or leathery black wings. Creating and dismissing these wings are a bonus action. Your flying speed is equal to your walking speed.

Unrelenting Presence

Once per long rest anyone of your choosing within 120ft radius must make a Intelligence saving throw against your spell save DC. If they fail they take 15d6 Psychic damage and are frightened of you as you entrust their consciousness into the depths of the nine hells if you gained this subclass by devil or the abyss for demon . If they succeed they take half of 15d6 psychic damage and aren't frightened.