This is a custom modern deck that wins through getting a Demon Of Death's Gate into play as soon as possible and then winning via a single hit with infect or repeated attacks for damage!
This may be a not so typical Demon of Death's Gate deck built to destroy your opponent in one blow. It is built around getting Demon of Death's Gate + Tainted Strike happening as quickly as possible using the alternative casting cost of the demon.
The deck is filled with quality one drops to get out the demon along with getting a little advantage. Vampire Lacerator, Death Cultist, Mortician Beetle and Fume Spitter all offer something when you are sacrificing them to get out your demon.
So spend 6 life, sac 3 of them and you get n enormous 9/9 flying and trampling demon!
That's great by itself, but then there is some added special sauce in the mix with
Tainted Strike. Cast this and if your demon lands a hit on a player, that's game with 10 poison counters in 1 hit!
Then to protect your demon the deck goes outside the box to Not of This World. It protects the demon at instant speed, and best of all, costs ZERO to play because of the demon's power!
The rest of the cards are some utility and removal; Sign in Blood gets you 2 cards for 2 life. Grasp of Darkness is there for removal. Vampire's Bite is early-game beatdown off your 1 drop weenies or a huge finisher with your demon. And it's lifegain offsets your Vampire Lacerator upkeep and Sign in Blood cost.
Typically, the deck plays out pretty quick but in case it stalls or you need some serious gas there are also 2 copies of Liliana Vess. She is in here for for her amazing utility and possible alt win condition if your opponents filled their yards with some nice fat creatures.
So if you like Suicide Black kind of styles or play aggro decks that trick things into play or if you like decks that can win the game in one hit then this deck is for you!
Here is the card breakdown:
The Creatures:
Death Cultist: This card begins the list of one drop creatures that you will sacrifice to get your Demon of Death's Gate into play. Aside from that, you can always sacrifice it to it's own ability. Sometimes 1 point of life loss will finish a game. And it can be early pressure at the start of a game.
Demon of Death's Gate: This is the card that the entire deck is built around. Resolve this creature, especially by using it's alternate cost, and you can easily win games with it. An Evasive 9/9 with trample needs to be answered immediately or not at all. Possibly coming into play as early as turn 2 and then combined with Tainted Strike for a 1 hit win. Then protect it while it is in play with Not of This World.
Fume Spitter: This is a great 1 drop creature that can serve as a roadblock and creature removal. The ability to block and then sacrifice it can sometimes let it trade up versus your enemies.
Mortician Beetle: Another one of the sacrifice creatures but this one serves double duty. The ability for it to grow from anyone sacrificing creatures can come in handy and even offer another way to win. Get a few counters on this and then combine it with Vampire's Bite or Tainted Strike. Your demon may be the best target for these cards but it is not the only one.
Vampire Lacerator: This is a great first turn drop that can pressure your opponent early while you drop creatures prepatory to the big sacrifice to get your demon. 2 power beatdown for 1 mana is always good and the disadvantage is offset by how quickly games can go or using your lifegain from a kicked Vampire's Bite.
The Other Spells:
Grasp of Darkness: This is solid, instant speed removal without any real disadvantage. This kills past regeneration and indestructibility.
Not of This World: No one expects a counter spell from a mono black deck. Let alone one that potentially can cost 0 mana. Sure you can use it on other things and spend 7 mana to cast it. But it is primarily in the deck to protect your Demon of Death's Gate long enough for you to get a win. And casting it to protect your demon costs 0 mana.
Tainted Strike: This card lets you win the game with 1 attack from your demon. Cast this whenever you can get in unopposed and you deliver 10 pts of poison counters to your opponent. You only need to give them 10 counters to win. Can also be used in the combat step to remove a pesky creature or downsize a threat.
Vampire's Bite: This card is just amazing at what it can do in this deck. It can be a finisher when cast on your demon. It can up your life total out of range of your opponent while you work on your win condition. And it can let your weenie 1 drops kill mid-range threats. At instant speed which makes it quite useful.
Sign in Blood: These are in the deck to help you through stalls or after emptying your hand. The life lost is a small price for a 2 card draw.
Liliana Vess: Besides Liliana serving as an alternate win condition in the deck, she also can help tutor for your win condition pieces. And since this deck is sacrifice and kill heavy, her ultimate is very useful. Besides all that, she is the Queen of Black and finds a place here.
That is it for the Deck! Add some swamps and suicide, err, sacrifice your way to the win!