The tieflings connected to Nessus command the power of fire and darkness, guided by a keener than normal intellect, as befits those linked to Asmodeus himself.
Ability Score Increase. Your Intelligence score increases by 1, and your Charisma score increases by 2.
Infernal Legacy. You know the thaumaturgy cantrip. Once you reach 3rd level, you can cast the hellish rebuke spell once per day as a 2nd-level spell. Once you reach 5th level, you can also cast the darkness spell once per day. Charisma is your spellcasting ability for these spells.