Robin Cornwallis is the 3rd child of Oliver and Finch Cornwallis. Despite her mom and older siblings all being tieflings, Robin is by all accounts human; the only inhuman thing about her is her sharp fangs.

She'd easily be able to pass off as a normal human, but Robin doesn't particularly care about those offended by her fiendish blood, and she takes pleasure in flashing a pearly white semi-threatening smile to whoever rubs her the wrong way, just to make them uncomfortable or offended.

She's kind of an asshole.