@drunkcynic - Thanks for the feedback! I was using
Rakshasa's Secret to help delve
Empty the Pits (which I have since moved to the maybeboard) and
Murderous Cut (when sideboarded). I liked
Rakshasa's Secret (and
Mind Rot) because the opponent loses two cards rather than one - and which also gives you the option to play
Rakshasa's Secret even if you don't have
Waste Not on the board. There's also a synergy between
Dark Deal and
Fate Unraveler, but usually my opponent doesn't have that many cards in hand around turn 4 or 5 to make a
Dark Deal play that valuable.
That being said I just got four
Dark Deal yesterday, so I'll try them out, however if I'm going to play
Dark Deal, I may look for other delve cards to include. Unfortunately there aren't too many great ones for mono black - although
Dead Drop may be an option. If you ran a blue-black deck, you could fuel things like
Treasure Cruise.