This is the deck Gabriel Nassif and I both decided to play at Pro Tour Kaladesh.
The Pantheon was having some success in testing with Red-White Vehicles, Red-Green Cub Energy, Black-Red Aggro, Aetherworks Marvel Combo, and Blue-White Control. It didn’t feel to us like a slow black-green control deck was going to have an easy time with a field of such diverse opposing threats. But an aggressive black-green deck affords you the luxury of a clock. Now, you could beat those slower Marvel draws. You could win when you didn't draw Ishkanah or when it wasn’t enough to hold things down for multiple turns. You could kill someone while Emrakul sat in their hand rather than having to win after they cast it.
A couple key innovations for us were Sinister Concoction and Scrapheap Scrounger. Sinister Concoction, on the surface, looks very bad. You are usually 2-for-1’ing yourself and you have no madness in the deck to prevent that (Scrounger counts for something though). But we wanted our removal to be cheap, versatile, and delirium enabling. On those 3 factors, nothing really came close to Sinister Concoction.
It’s worth noting something Nassif and I didn’t realize until I asked a judge at the Pro Tour: You can mill the card from Concoction before you choose which card to discard. This is actually pretty important since it means delirium is reliably, not randomly, going to be turned on when you sacrifice Concoction with even as little as 1 Traverse in your graveyard. In a deck with no Vessel of Nascency or Grapple with the Past, this card proved to be an important component.
Scrapheap Scrounger was a perfect way to be able to pilot Smuggler’s Copter again and again. It also has 2 card types, which again makes delirium easier. Using removal against it is obviously not great for the opponent, and it attacks for 3 which makes it good pressure.
For the sideboard, we tried Lost Legacy and Transgress the Mind, but then we realized the card Pick the Brain was a better version of both cards. It does both things. It doesn’t miss. It solves the problem at hand not the problem you guess is at hand. It's another key card that we would have played 4 copies of had we realized the Pro Tour would be 20% Marvel decks.
Key to the City becomes a vital card against opponents who try to use Ishkanah to stop you from attacking. Ishkanah is really annoying to attack through. Verdurous Gearhulk helps, but Key to the City trumps.
To the Slaughter is really important versus anyone with Blossoming Defense and Blistering Hydra in their deck. It can also kick Gideon’s butt if you need it to. I might play 3 copies of that card going forward as I expect those decks to stick around or even increase in popularity.
Changes you should consider (not necessarily make, just consider) if you pick up this deck moving forward:
-1 Dead Weight
+1-2 Blossoming Defense
Moving Tooth Collector to the Sideboard
Moving a Pick the Brain to the Main Deck
Kalitas Main Deck