Imp-Wise Halfling (5e Subrace)
From D&D Wiki
Imp-wise halflings have had their blood tainted by fiendish heritage. They are distant relatives to some demonic being and have their appearances mildly reflect this. They have sharper, more jagged teeth, a forked tongue, and paler skin compared to other types of halflings.
Ability Score Increase. Your Charisma score increases by 1.
Slippery Devil. When you aren't wearing armor, your AC is 13 + your Dexterity modifier. You can use your natural armor to determine your AC if the armor you wear would leave you with a lower AC. A shield's benefits apply as normal while you use your natural armor.
Twisted Heritage. You can speak, read, and write Abyssal and Undercommon.