This is a grindy sacrifice-vs-midrange fight where Sheoldred, the Apocalypse punishes our card draw and Graveyard Trespasser pressures our graveyard, so Dark Betrayal and Fatal Push give us cheap, efficient answers. Dark Betrayal kills Sheoldred and their other black creatures, though it can't hit green Badgermole Cub or a colorless Mutavault. Fatal Push handles their cheap creatures like Badgermole Cub and Graveyard Trespasser, and it can reach Sheoldred when we have revolt active, such as after sacrificing a Treasure or Food. Tormod's Crypt gives us a cheap way to exile their graveyard and blunt their graveyard plans, such as Takenuma, Abandoned Mire. We trim Thoughtseize since their hand empties fast and they have their own discard to fight over. Lively Dirge gets weaker because Culling Ritual punishes our small permanents. Umbral Collar Zealot is a low-impact body against their efficient removal suite (Fatal Push, Abrupt Decay, Bitter Triumph).

Indomitable Creativity and a critical mass of counterspells (Spell Pierce, Spell Snare, Mystical Dispute) make our proactive sacrifice plan good, but we need cheap interaction for Atraxa, Grand Unifier and Raph & Mikey, Troublemakers that Indomitable Creativity can cheat in, as well as for Fable of the Mirror-Breaker's token. Fatal Push answers the Goblin Shaman token from Fable (mana value 0 after cost reduction isn't relevant, but the base 2/2 token dies to Push) and cheap creatures cast via Creativity hits, while Dark Betrayal isn't ideal here since many of their big targets aren't black, so we only bring a light removal upgrade. Thoughtseize is weak since this is a low-interaction, proactive deck that doesn't rely on a single key card we can strip early. Umbral Collar Zealot is replaced since it doesn't advance our clock fast enough against their card-advantage engines.

Selesnya Company is a creature-dense aggro-midrange deck, so Fable of the Mirror-Breaker's chapter I Goblin token and Treasure generation gives us card advantage and a blocker while chapter II smooths draws. Dark Betrayal is a cheap answer to any black threats they board in, though most of their mainboard is colorless or green/white so it's a situational include. Thoughtseize is less impactful against a low-curve creature deck that doesn't rely on key spells, so we cut to two copies. Umbral Collar Zealot doesn't do enough work against their proactive curve, so we trim two copies to make room.