Shadow Tiefling (5e Race Variant)
From D&D Wiki
Everyone knows the story of how some humans of a large and lost empire, in search of power, made a pact with the overlord of Nine Hells, infusing its essence and cursing their entire generation forever. But what many do not know is that after the fall of the empire, some survivors of the newly created race still sought for power. Among these, a man whose name is long forgotten traveled to the darkness of the shadowfell, and there his descendants were touched by the shadows. Their heritage went beyond the infernal pact. It transformed their skin in shades of gray and their hair went from white to black. Even the fire that runs through their veins was touched by the darkness.
A shadow tiefling has the following traits, which replace the tiefling's ability score increase, darkvision, hellish resistance and infernal legacy.
Ability Score Increase. Your Dexterity score increases by 2 and your Charisma score increases by 1.
Darkvision. 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.
Dark Resistance. You have resistance to necrotic damage.
Fell Legacy. You have proficiency in the Stealth skill. When you reach 3rd level, you can cast the heritage rebuke as a second-level spell once and need to finish a long rest before you can cast it again.