Before I start, I have to acknowledge the work done by other players in putting this together, namely the slumbering spirits build by pickle the kid on mtg goldfish and giantmonstergames on here. Also, tedg's tora tora tora build on mtg goldfish.
I started out doing essentially these decks and taking them to Modern night and they are just to slow to be competitive. I would never win a game let alone a match. So I put together the list as sort of an attempt at what I could combine between the three and what was the quickest most effective strategy.
Role of each card:
Tora: Mid Game Aggro and Distraction, (Tora is to expensive and slow to be dangerous in modern. However, if you are playing a slower deck getting it on the field can alter a player's mana use (they may attack) at the expense of say a mind shrieker. It also gives you a discard outlet, whether or not damage goes through, (depending on what the battlefield lookslike) you can get a card to your graveyard and do a noxious revival or Goryo.
Mind Shrieker: Your primary win condition, Turn 1 training grounds, turn 2 mind shrieker, turn three you can do two flips and save a prot spell or game ender on the back burner (tainted strike, apostles or Noxious Revival) if you have three lands and can potentially clean house and win it. The 1 mana drop flip with training grounds is great. Further let's say you are sitting fine turn 3, drop some mystic speculation /taigams and keep the rest for a turn four win.
Noxious revival: lets creature cycle from the graveyard to library for shrieker and get it to your hand for tora, you can also use it to get scry and draw back as needed.
Apostle's blessing: This your protection/hexproof/unblockable to keep creatures on the field. First it's unexpected as you are running blue black, second if you are facing a monocolored deck or a deck where you know the sole color of their creature removal you can use it like a hexprrof distortion strike. All around its a nice little utility card.
Training grounds: The essential but also filler card the only reason this card is here is a turn 1 drop, after that you have 3 junk cards filling your deck. However, the net benefit to spirit slinging with a 1 trigger is paramount. Also, they can be uniquely useful, on rare occasions, such as if you have them while playing the rack to fill your hand.
Goryo: Strategic offense when wanted, defense when needed. Goryo allows a double up on the Tora Shrieker abilities to finish a game. It can also be used as a defense. Iname as one Goryoed into a death toucher is tons of fun and Goryoing a Sekki into something large also yields its own rewards which I will get to later.
Tainted Strike: makes the deck a one hit wonder.
Taigam scheming: lets you see 5 turns ahead, this is a big card if you are in the mid to late game, you can clear out what you don't need and get straight to the creatures, or get the creatures to the graveyard for noxious revival or Goryo.
Mystic speculation: For the scry to set up your next or the current turn.
Iname as one: turns a 1/1 in a 13/13 on turn three that you can swing with. If you bring it back to the field and on defense, with goryo you can run it into a death toucher and trigger its ability to bring a spirit permanently back from the grave.
Sekki: 8 drop turns shrieker into a 9/9. The real fun begins if you get to Goryo him into something big. Even though he is an 8/8 if he runs into a 10/10 his triggered ability creates 10 1/1 spirits you can sack 5 and turn your Westvale abbey if you are in a long game. Or you can sack 8 and bring Sekki onto the field permanently.
Myojin of life's web: Just a big 9 drop that buffs our shrieker to 10/10. No special abilities you will be able to use, you can consider Kuro Pitlord, myojin of seeing wind, or the unspeakable as potential substitutes.
How to play: This is a combo deck that requires a specific draw, minimum 2 lands, ideally 3. At least 1 mind shrieker and training grounds are essential. Then apostles, a scry of some sort would be my next hope. You want to avoid hands with the big creatures in them because they won't be doing anything until turn 4 or 5. The London Mulligan will really help this deck perform, and its a bit awkward to get used to but can be a lot of fun. Any questions recommendations feel free to jump in give thoughts.
Sideboard:
Evil Presence/Sea's claim: These are for tron/celestial colonnade tefari decks. You either slow down tron or evil presence a plains to stop them from using creature removal. I have experiemented with tron on this and it helps
Vapor snag and Mystic speculation: Self-explanatory, vapor snag is great against infect, mystic give you more easy setup.
4 Stream of thought and 2 more noxious revivals
That's all I have, feel free to give thoughts.
-Joe