So tested this out on two Competitive leagues got 4-1 and 5-0 and won Tuesday Night Magic. It loses the energy, takes the Sultai Structure, and builds a powerful control deck.
So pretty much, the deck plays out as a traditional control deck. Draw-Go, remove and counter. Carnage Tyrant plays a solid finisher, Scarab God let's you pick up after your destruction, Torrential Gearhulk plays a great defender, flashing back removal or card draw, and is great call back card, especially with Liliana, since it plays a triple threat threat with Scarab God. Hostage Taker gives you great defense, forces them to use their resources, and later once their worn out, or you have counter protection, it lets you gain substantial advantage. Bontu's Last Reckoning has consistently been effective against Temur, Sultai, and Four Color Energy, and the drawback, has been little to none. Disallow and Supreme Will obviously have their benefits. Vraska's Contempt has been exceptional, but, work as a two or three of, the four of just doesn't seem to work.
Originally had Yahenni's Expertise in the sideboard when I wasn't sure of Bontu's reckoning. Bontu's Reckoning plays it so much better. Lost Legacy and Duress are necessary for U/W Control and B/W Tokens. I still prefer Negate over Spell Pierce, though if the move on modo goes from B/W Tokens or Temur Energy or U/W Control, to another aggro deck, spell pierce may make a better card. Doomfall is perfect against mid-range creature decks and great hand destruction when nothing else is happening. Appetite for the Unnatural is great because of both token decks that are floating around. Esper and B/W Tokens. And Sentinel Totem as well is great for Esper Gifts and other decks (which is most of them) that are aiming to dominate with a The Scarab God.
I want to like a good Sultai Control list, but yours is way too top heavy. You have seven cards in the 6CMC slot and only three cards at under 3CMC. I might want to shave down the top end stuff and maybe the Doomfalls for a mix of Negate, Essence Scatter, or Censor, although I'd focus first on a full set of Aether Meltdown.
Secondly, what's with Glacial Fortress if you're not playing white? It gives no advantages and you're better off playing islands, but I would switch them with Aether Hub now that you're generating energy with both Glimmer and Meltdown. It also increases the number of green sources for Vraska. Concealed Courtyard is also a head-scatcher in a sense that you're not playing white, and I think you meant Botanical Sanctum? Lastly, I would replace the Irrigated Farmland for the two more Fetid Pools.
wrote the mana up too quickly and wrote that by accident. Was writing off the top of my head while distracted, wasn't getting that down right at all. Made changes that were in my list now that I was looking at it. Have Aether Meltdown and Walk the Plank.
3x Glimmer of Genius
2x Vraska's Contempt
2x Disallow
3x Fatal Push
2x Doomfall
2x Bontu's Last Reckoning
2x Walk the Plank
4x Hostage Taker
1x Carnage Tyrant
2x Torrential Gearhulk
2x The Scarab God
2x Vraska, Relic Seeker
1x Liliana, Death's Majesty
4x Blossoming Marsh
4x Botanical Sanctum
2x Fetid Pool
3x Evolving Wilds
2x Forest
3x Island
3x Swamp
1x Bontu's Last Reckoning
1x Doomfall
2x Appetite for the Unnatural
2x Negate
3x Duress
3x Lost Legacy
2x Sentinel Totem
So pretty much, the deck plays out as a traditional control deck. Draw-Go, remove and counter. Carnage Tyrant plays a solid finisher, Scarab God let's you pick up after your destruction, Torrential Gearhulk plays a great defender, flashing back removal or card draw, and is great call back card, especially with Liliana, since it plays a triple threat threat with Scarab God. Hostage Taker gives you great defense, forces them to use their resources, and later once their worn out, or you have counter protection, it lets you gain substantial advantage. Bontu's Last Reckoning has consistently been effective against Temur, Sultai, and Four Color Energy, and the drawback, has been little to none. Disallow and Supreme Will obviously have their benefits. Vraska's Contempt has been exceptional, but, work as a two or three of, the four of just doesn't seem to work.
Originally had Yahenni's Expertise in the sideboard when I wasn't sure of Bontu's reckoning. Bontu's Reckoning plays it so much better. Lost Legacy and Duress are necessary for U/W Control and B/W Tokens. I still prefer Negate over Spell Pierce, though if the move on modo goes from B/W Tokens or Temur Energy or U/W Control, to another aggro deck, spell pierce may make a better card. Doomfall is perfect against mid-range creature decks and great hand destruction when nothing else is happening. Appetite for the Unnatural is great because of both token decks that are floating around. Esper and B/W Tokens. And Sentinel Totem as well is great for Esper Gifts and other decks (which is most of them) that are aiming to dominate with a The Scarab God.
Secondly, what's with Glacial Fortress if you're not playing white? It gives no advantages and you're better off playing islands, but I would switch them with Aether Hub now that you're generating energy with both Glimmer and Meltdown. It also increases the number of green sources for Vraska. Concealed Courtyard is also a head-scatcher in a sense that you're not playing white, and I think you meant Botanical Sanctum? Lastly, I would replace the Irrigated Farmland for the two more Fetid Pools.
Standard: BG Golgari Midrange
Modern: U Merfolk GWUBR 5 Color Humans UBW Esper Gifts GW Bogles