Shadowborn Apostle: There are 28 copies of
Shadowborn Apostle in the deck, and that's a bit on the light side. It is challenging to fit other pieces into the deck when one card and its multiple copies are so important. The text on
Shadowborn Apostle allows us to circumvent the singleton rule of EDH/Commander by including multiple copies of the same card: "A deck can have any number of cards named
Shadowborn Apostle." When we tap
and sacrifice six creatures named
Shadowborn Apostle we can search our library for a demon creature card and put it onto the battlefield. This is not a demon tribal deck. However, we do have some demons in the deck. One variation of this engine is to continue to sacrifice the
Shadowborn Apostles in order to fetch-out demons, have the
Shadowborn Apostles return to our hand because of a down-on-their-life-total opponent won't pay 18 life to keep them in the graveyard, cast the
Shadowborn Apostles, lather, rinse, repeat. This will put some demons onto the battlefield for us. Most likely, however, they will not be enough to directly knock-out our opponents. However, what these demons can do is what makes them so valuable.
Ob Nixilis, Unshackled: Obee-Nix-Kenobi! This demon from Magic 2015 is very valuable in this deck. Ob Nixilis, Unshackled is a 4/4 flier with trample and whenever another creature dies he gets a +1 +1 counter. Note this text closely. "Whenever ANOTHER creature dies." It's not "whenever a creature we control dies." It's not "whenever a nontoken creature dies." Any creature from the battlefield. Ours. Our opponents'. Fetching-out another demon by sacrificing six Shadowborn Apostles will put six +1 +1 counters on Ob Nixilis, Unshackled regardless of whether or not an opponent pays three life for each Shadowborn Apostle dying if Athreos, God of Passage triggers. Additionally, whenever an opponent searches their library, that player sacrifices a creature and loses ten life. On average, how many times per game does an EDH/Commander player search their library? With an opponent's trigger on the stack, fetching-out Ob Nixilis, Unshackled in order to see an opponent sacrifice a creature and lose ten life feels good. It feels really good. How can feel any better? Let's activate and sacrifice Field of Ruin and destroy a nonbasic land an opponent controls. Each opponent then searches their library for a basic land, sacrifices a creature and loses ten life. Ob Nixilis, Unshackled can do some malicious things in this deck!
Razaketh, the Foulblooded: It just got real. Razaketh, the Foulblooded is an 8/8 flying trampler that costs . His beefy body aside, we also can pay two life, sacrifice another creature and search our library for a card and put it into our hand. Demonic Tutor on a stick! We're planning to send many, many Shadowborn Apostles to the graveyard, so sacrificing one and paying two life in order to Demonic Tutor is not a hardship. We'll need to utilize some tutors in order to gather pieces for our engine, and Razaketh, the Foulblooded provides this service in addition to an evasive beater. Auto-include.
Rune-Scarred Demon: The addition of this demon is more straight-forward. When Rune-Scarred Demon enters the battlefield, we search our library for a card and put it into our hand. This is another Demonic Tutor. The 6/6 flying body attached to Rune-Scarred Demon is a great addition.
Harvester of Souls: This is a 6/6 demon with deathtouch, but not flying. What's up with that?! No flying!!? Seriously!? Okay, well, Harvester of Souls is a biggun at 6/6. This flightless demon is included due to its ability to draw us a card whenever another nontoken creature dies. We have a lot of nontoken creatures in the form of our Shadowborn Apostles and each time one of them dies, we will draw a card. Even if Athreos, God of Passage is under our control, the creature hits the 'yard in order to trigger Athreos, God of Passage, so if an opponent does not pay three life and a Shadowborn Apostle is returned to our hand, we netted two cards because of the Harvester of Souls's death trigger. Drawing cards is awesome!
Vilis, Broker of Blood: Here we have another 8/8 flying demon, but without trample. I suppose not all demons can be as big and as trampley as Razaketh, the Foulblooded. Anyway, Vilis, Broker of Blood provides some interesting abilities. We can pay and two life in order to give target creature -1 -1 until end of turn. Additionally, whenever we lose life, we draw that many cards. Basically, each time we activate Vilis, Broker of Blood's ability we will draw two cards. Similar to Harvester of Souls, Vilis, Broker of Blood will ensure that we have a fistful of cards in our hand.
Zulaport Cutthroat: Zulaport Cutthroat can be one of the pieces to our Athreos, God of Passage engine. Whenever Zulaport Cutthroat or another creature we control dies, each opponent loses one life and we gain 1 life. It's Zulaport Cutthroat's text that makes him so valuable, as "EACH OPPONENT LOSES ONE LIFE" is the key. This is not Blood Artist. We do not have to target one player. Every opponent is greater than target opponent. Zulaport Cutthroat also dances around hexproof and shroud. Blood Artist just stays on the battlefield clutching his easel if our opponents have hexproof or shroud. Additionally, Zulaport Cutthroat forces opponents to LOSE LIFE. Blood Artist deals damage. Understandably so, this is meta-specific, but Glacial Chasm is a thing and Zulaport Cutthroat side-steps it with ease. I prefer Zulaport Cutthroat in this spot for all of the reasons above, including his awesome flavor text.
Syr Konrad, the Grim: Syr Konrad, the Grim takes the action of creatures hitting graveyards to additional levels. When any creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves our graveyard, Syr Konrad, the Grim deals one damage to each opponent. I do wish "each opponent loses one life" as opposed to "deals one damage to each opponent." That would probably make Syr Konrad, the Grim unstoppable. He also has a built-in mill option. Tap and each player mills the top card of their library. This addition from Throne of Eldraine can serve as another key cog to our Athreos, God of Passage engine.
Luminous Broodmoth: This insect can play a pivotal roll in our Shadowborn Apostle engine. Whenever a creature we control without flying dies, we return it to the battlefield under its owner's control with a flying counter on it. As our flightless Shadowborn Apostles hit the graveyard, Luminous Broodmoth returns them with a flying counter firmly affixed to the card. This allows us additional opportunities to sacrifice and recur our Shadowborn Apostles with or without the presence of Athreos, God of Passage: REMINDER: Death triggers stack, so stack accordingly based on the state of your game and board!
Teysa Karlov: My heart belongs to Teysa. It seriously does. Seems like a good title for a country song. Anyway, if a creature dying causes a triggered ability of a permanent we control to trigger, that ability triggers an additional time in the presence of the great Teysa Karlov. More damage. More life lost. More life gained. More treasure tokens created. DOUBLE triggers for Athreos, God of Passage. If an opponent is hemming and hawwing about paying three life for a creature to stay buried in our graveyard, I can't imagine there will be a lot of deliberation from that same opponent if they have to pay six life to keep the creature underground. Teysa Karlov speeds-up our end-game engine by doubling every death trigger we have. That's our end game. Our Shadowborn Apostles are going to die, and we hope that Teysa Karlov will be there to watch it happen.
Edgewalker: You think you know me...Edgewalker reduces the casting cost of our Shadowborn Apostles from to free. How disheartening it must be to watch Shadowborn Apostle after Shadowborn Apostle get returned from our graveyard to our hand by an opponent not paying three life, then to see us cast them for free and continue the process of sacrifice-recur until the game is over. Edgewalker can be a piece to our Athreos, God of Passage engine.
Taborax, Hope's Demise: This demon from Zendikar Rising checks a lot of boxes for what this deck wants to do. It has a very manageable mana value of , which becomes just if Edgewalker is under our control because Taborax, Hope's Demise is ALSO a cleric. Taborax, Hope's Demise flies and has lifelink it has at least 5 +1 +1 counters. Most importantly, whenever another nontoken creature we control dies, we put a +1/+1 counter on Taborax. If that creature is a Cleric, and it WILL BE, we may draw a card. If we do, we lose 1 life. The "may" clause from the card-drawing trigger is significant, as a lot of black spells force the card to be drawn. With this option, we can be mindful of our library size and life total. Tabby's got a place in this deck!