Black devotion deck based on the good ol Gray Merchant of Asphodel, get the devotion up, kill opponents creatures win the game, that simple!
So first off I wanted to answer probably the biggest question someone may have regarding this deck, and it has to do with why I use 2x Temple of Deceit and 2x Temple of Silence the answer is quite simple. Lets say I am getting Nightveil Specter out and getting cards from opponent, if they are running blue or white I can typically play them off my own mana and don't need to rely on hitting a land from them. Of course this isn't guaranteed I personally think it is overall better than running just 2x Temple of Deceit
The other cards in the deck are just heavy kill spells with Hero's Downfall, Devour Flesh, Doom Blade and Ultimate PriceThey typically get the job done!
Pack Rat can be devastating to anyone, activate a Mutavault and suddenly your rats become massive.
Other cards in the deck give us great card advantage such as Underworld Connections and also give plenty of devotion with double black in both the Underworld the Desecration Demon and the Whip of Erebos.
Nightveil Specter - I believe that this card is the all star of the deck overall, not only does it provide a substantial 3 devotion but it also has evasion and can net us some sweet cards from the opponents deck. Pretty awesome card in my opinion.
Thoughtseize - A VERY powerful card right now, and since we run the whip we can typically afford to pay the 2 life without worry. This makes a beautiful first turn play.
Erebos, God of the Dead - A great indestructible powerhouse when devotion is high, as well as not letting opponents gain life. Which is awesome for the mirror match, I would run a second copy against the mirror.
Thats basically the deck in a nutshell, some changes may come up as I am debating on splashing green but for now mono-black is cheap, easy to use, and will win games. Thanks for checking it out! If anyone has some suggestions outside the box that would be great! Always looking to impove! If you like it spam that +1 button.