This deck is inspired by SaffronOlive at MTGGoldfish
Since that article was published, BFZ came out, giving us Zulaport Cutthroat as Blood Artist 5-8, as well as Carrier Thrall as another 2-CMC vampire who replaces himself.
This deck wins by incrementally draining our opponent's life through Blood Artist and Zulaport Cutthroat, with assistance from Geralf's Messenger. We can sacrifice our own creatures to Viscera Seer, which acts as virtual card advantage, to Bloodthrone Vampire which is sometimes able to get in for big combat damage, or to Cartel Aristocrat which is a phenomenal blocker, or a pretty guaranteed 2-damage on the attack.
Our opponent needs to always be afraid, much like they're facing Twin. With Rally the Ancestors and Cauldron Haze, instant speed wins are possible from any life total, and very likely under ~13.
Cuts from MTGGoldfish's version:I didn't care too much for Kalastria Highborn because of the mana requirement to drain. Removed 4 copies.
Pawn of Ulamog: This is awesome for making all your creatures replace themselves, but at 3CMC it isn't valid for Return to the Ranks so it's a reasonable trim. Removed 1 copy.
Gatekeeper of Malakir: While 2CMC and strong kicker, this is a pretty bad card to reanimate, and we're adding in removal with Teysa. Removed 4 copies.
Adds:Zulaport Cutthroat: We didn't have much of a win con if we didn't hit a Blood Artist. An additional 4 copies of the card is INSANE. While it doesn't trigger from our opponent's creatures, our own creatures die way more frequently so that's hardly a problem. Added 4 copies.
Cauldron Haze: I am also experimenting with cutting 2x Return for 2 copies of Haze as an additional instant speed win con for only 2 mana. Haze does rely on us having a board, but it feels like it threatens a kill so much more easily if we run a copy. Few notes: Haze can be used on our dudes with 1 toughness; they will simply come back and die right away. It can also be used for value if the opponent has some amount of 1-toughness dudes about to die and we have Blood Artist (NOT cutthroat) out. Did I mention this can go NUTS with Geralf's Messenger?
Flex slots:This deck needs sac outlets and drainers; those account for 18 cards. 22 lands feels right, as does 8 reanimation spells and 3 Path to Exile. That leaves a whopping 9 flex slots. Currently I have a bunch of value 3-drops in there: Geralf's Messenger x 4, Pawn of Ulamog x 3, Teysa, Orzhov Scion x 2. Honestly, I have no idea what the right cards are for these 9. The Maybeboard reflects options for these slots. Hell, it might be correct to run Tidehollow Sculler and Fulminator Mage in the main cause of how sick they are if given Persist.
Sideboard:Leyline of Sanctity isn't TOO bad because Cutthroat doesn't target, but we have a lot more trouble winning if it's out. Rest in Peace is brutal, and Grafdigger's Cage is bad. Our sideboard strategy brings in creatures to take care of these roadblocks for us, so we don't need to weaken our reanimation spells too badly by playing too many Disenchants! That's right--no transformative sideboards here, we intend to fight directly through the hate cards our opponent brings in. War Priest of Thune is simple. Leonin Relic-Warder and Tidehollow Sculler not so much. See, when they ETB, they can be sacrificed while their ETB triggers are still on the stack. This makes their leaves the battlefield abilities resolve first, returning nothing to the battlefield/their owner's hand. After that, their ETB trigger will resolve, exiling a card permanently. Pretty nasty, huh?