The goal is to keep the opponents side of the field empty with all the black removal suite. Then win by bringing Gray Merchant back to the field over and over.
The combo is Palace Siege and Gray Merchant. You can block with Gary to kill him, or kill him yourself with Languish or even a single target spell. Then you just Siege him back into play again.
Erebos's Titan - Great 4 drop that really locks the field down and leads into a turn 5 Gary. - Often the Titan will be killed when you play it because its the first target-able creature and your opponent has a handful of removal. The way to stop this is of course to have removed their board first so Titan comes down indestructible. Running 3, because 4 is too much and 2 is not enough
Merciless Executioner and Fleshbag Marauder - They're great because of the interaction of flipping Liliana and the fact that you can Siege or Whip to bring them back. The upside is they don't target anything in particular, so it gets through hexproof and other targeting annoyances. The downside is if they have a weenie or 2 to sac, then their usefulness is minor. I ran 4 of each at first because they seemed so good, but found that 4 total was enough. 2 of each as opposed to 4 of one for obvious reasons.
Gray Merchant of Asphodel - core card. I tried running 4 of, but he really ended up clogging my hand. 3 is more than enough, especially since you really only need 1 to get the recursion going. Dont get greedy with Gary. Him hitting the board for 4 or 5 is great. He doesn't need to hit for a large number like 9. He will come back again. The 4 or 5 he nets you the first time you play him is usually enough to stall the opponent for long enough that you can get the combo off.
Erebos, God of the Dead - card advantage. Thats mostly what he's here for. With all the life gain you can usually use him to get crazy CA. also he frequently becomes a 5/7, though I find that he often gets exiled as soon as he's a creature.
Bile Blight, Hero's Downfall, Murderous Cut, Ultimate Price - Black removal. Still working on the numbers. Ultimate Price and Blight are great because of the 2cmc cost. I might want to up the number to 3 Blight because of how many elves, goblin, token, warrior decks I run across. Downfalls are for anything, and the Cuts are a great way to cast 2 spells in 1 turn. Anytime you can cast a removal for 1 is a good time. Remember don't delve away your creatures unless necessary.
Whip of Erebos - Its a whip. Lifelinking your Titans is great. also lets you bring back dudes if you need to. Think of it as a backup Siege. In case all your Sieges get removed for some reason, Whip can get you the win. Also Lifelink!
Languish - When the board is flooded with a bunch of tiny dudes, this will clear the way. 3 main might be the way, but I haven't done enough testing yet.
Sign in Blood - Better than Read the Bones because I needed more cards in the 2cmc slot. If you run Read the Bones, then you have to Mulligan hands with 2 lands. Its too dangerous with this deck. With Sign in Blood you can keep a 2 land hand a little more comfortably.
Liliana, Heretical Healer - Her lifelink is often a key part of helping you survive until you can Siege. Her flip is easy to get with the Sac guys we are running. She is another way to get creatures back onto the field. If you need to you can play a sac guy, flip her and then use her ability to bring the sac guy back again that turn. Once you have Sieges in play, there are a bunch of ways to use her and your creatures to maximize you card advantage.
Dark Petition - Its good. There are times where you need that specific card to win, or more likely to blowout their side of the board so you can stabilize. Im finding in my meta it is Languish that im looking up, so I might just run 1 more. But Dark Petition's utility is just great.
Sideboard - still a work in progress.
