You need Liliana's Specter and Okiba-Gang Shinobi in this deck. Also replace Murder with Victim of Night.

Altoman, Liliana's Specter seems nice, thanks for this.But Victim of Night too limited, I guess. In the games I played it didn't work so well. This rat has a high cmc for the deck, so I pass.

Since you're asking...

I tried it on my mono-blue Delver control and it stomps you. On the other hand, if your local play radius doesn't include much Delver or blue control, you might not care.

I urge reconsidering the Victim of Night. It really is good against the majority of the meta, unless all you play against is vampires and zombies. Even in the sideboard it looks better than Sinister Possession. Other good mono-black removal includes Geth's Verdict and Disfigure, good against Bogles and Delver respectively.

For your strategy, Augur of Skulls is good. You run too light on threats; you just can't race in the air like the faster decks can. Augur can force the 2 discard just like Mind Rot and still carry a Bonesplitter when the point comes to go offensive.

Instead of Mind Rot I would go Wrench Mind. And i would go 4x augur of skulls: he is your best opener. Take out a couple of Raven's Crime. Is too wide, and u virtually need just one in your graveyard to keep using it. Put a couple of cycling lands.

I don't think Quag Vampires is good enough. Maybe in the sideboard against other black decks. Chittering Rats is a much better creature and literally gives you an extra turn, because your opponent draws the card again in the next turn. In addition, i would change Murder with either Victim of Night or Grasp of Darkness. Both spells have the same Mana cost and kill nearly all creatures in the format.

Thanks fAPE, I really like those rats.