This is my version of the relatively standard Shadowborn Athreos deck.
Deck Premise:
This deck leverages, the low costed. Shadowborn Apostle's ability to have any number in your deck to A) combo with Thrumming Stone to play every copy in your deck or B) Generate a value engine of reoccurring Black Weenies using Remembrance or Athreos' ability.
Once you have a large amount of Apostles on your board, you can use their second ability to fetch up one of your overpowered demons (usually Razaketh) directly to the board.
Winning the game:
With Razaketh, you can search out all of your combo pieces and win the game. Usually, this will involve infinitely casting Shadowborn Apostles using Athreos ability (pointed at an opponent with the lowest life) + a sac outlet (Phyrexian Altar or Vicera Seer) + Edgewalker. Once you have this loop, you beat your opponents by creating a massive storm count and using Tendrils of Agony or by draining everyone out using Zulaport Cutthroat/Bontu's Monument.
Weaknesses:
This is a creature combo deck that requires three specific cards and the graveyard to go off. Disrupting any of these pieces can set you back drastically or even put you out of the game outright. Our biggest threat is Leyline of the Void and Rest In Peace as they turn off the zone that we need to return our threats.
If anyone of our combo pieces is exiled or completely turned off, our back up plan is to use Athreos' ability and a life drain permanent to grind opponents down and finish them off with one of our flying demons. It's much more challenging going this route.
This deck is mana hungry for colored sources. Smothering Tide has been a boon but I have been constantly been looking for more sources.
A final major weakness that applies specifically to my deck is that my Shadowborn Apostle count is actually a little low. Most Shadowborn decks run ~30, and I believe that the math would show that you should probably have about 28 minimum to go off w/ Thrumming Stone everytime. My deck runs 26 so that I can fit in more stuff. I accept the fact that Thrumming Stone will fizzle sometimes and it definitely has done so in the past. If you want to go off more often, run more Shadowborns in your deck.
Current Tinkering:
I recently replaced Faith's Reward with Luminous Broodmoth. Sadly, this deck is pretty mana intensive so you'll end a lot of turns tapped out making it much harder to hold up Faith's to counter a board wipe. Broodmoth gives similar protection while providing a flying body and lets you use your mana. The downside being that double white slightly difficult to achieve on curve and that it doesn't protect your big boi demons.
I've been looking for spots to add Bolas' Citadel and Dark Ritual to the list. Bolas' is an expensive combo/card advantage enabler that lets you use your life as a resource. Dark Ritual is extra mana early game fast mana. Both of these cards would really be to double down on the combo.
Phyrexian Arena should be Necropotence. But Necropotence just feels like a commander trope. I've also thought about adding Dark Confidant in this slot to drag down the mana curve, but it's a pretty expensive card.
Despark should probably be a Path To Exile or a Swords to Plowshare, but I've been enjoying the spice.
Lastly, I really want another piece of enchantment removal. I've been thinking about Seal of Cleansing but I don't know what I would remove for it.
