Abrupt Decay: One of the best removal spells ever printer and can hit almost everything in the format.
Arena: Super scary for the opponent when combined with Phyrexian Obliterator. The way it's worded means we can use it on Obliterator when he is already tapped, making going on the offensive possible.
Bitterblossom: An amazing 1 of in this deck. This card has single handedly one me a multitude of games. Some decks just can't beat a board with Liliana of the Veil and Bitterblossom out there. It provides flying defense and chump blockers against other decks and counts for two card types in the grave
Bloodghast: An aggressive creature that won't stay dead. It synergizes well with all the discard outlets in our deck like Liliana of the Veil, Grim Flayer and Collective Brutality, making it a free creature that keeps the pressure on and ensures devotion on the board for when a Gary is dropped. This little guy is also likely to attract opponents' Path to Exiles which helps us ramp into much scarier threats which the opponent wishes they saved their removal on.
Deadly Allure: A spicy multi-use removal spell that has great synergy with Phyrexian Obliterator and Bloodghast
Fatal Push: The new premier black removal spell that can hit 99% of creatures in the format including manlands.
Gray Merchant of Asphodel: Gary is our closer in the bottom of the 9th. Underwhelming by himself, overwhelming with a Phyrexian Obliterator or any other devotion on board.
Grim Flayer: His ability to filter our draws is very powerful. He enables delirium for himself, adds B devotion to the board, and becomes a 4/4 trampling threat our opponent needs to find an answer to.
Inquisition of Kozilek: Efficient hand removal to get us to midgame
Liliana, Death's Majesty: She can close out a game by reanimating a Gary
Liliana of the Veil: Keeps them off cards, keeps their creatures in check, makes Bloodghast free, one of the best planeswalkers ever printed
Nihil Spellbomb: Shuts down grave based strategies, cycles itself, adds a revolt trigger, and adds a card type to the grave
Phyrexian Arena: Card advantage and 2B devotion on the board
Phyrexian Obliterator: The face of GOD, Saint Peter himself. "Now I am become Death, destroyer of worlds."
Thoughtseize: Efficient hand removal to get us to midgame
Traverse the Ulvenwald: Delirium is pretty easy to turn on in this deck making this a 1 mana tutor for a relevant threat. Grab Gary to close out the game or Arena to abuse with Obliterator