The Devil in the Dark The Devil is the Horta. The Devil is the devil men bring with themselves, themselves. Devil's Due Refers to the unpleasant payment that must be rendered, eventually, when making a bargain with the devil, whether made figuratively or literally, and which the inhabitants of Ventax II expected to pay. Refers to Ardra showing up per schedule, as anyone might be "due" at a certain appointed time: The Devil's due to show up today. Also, I think, Riker getting to stay on the Enterprise, and command it, even for a short time. Maybe also the way he looks at simply being 1st officer aboard the Enterprise--command of a sort (although not captaincy) and the best berth he can think of.