Damping Sphere turns the double-colorless mana from Eldrazi Temple (and Ugin's Labyrinth when it has an imprinted card) into a single {C}, slowing Emrakul and the seven-mana Devourer of Destiny. It also taxes extra spells each turn. Urza's Saga taps for a single {C}, so the Sphere does not slow it down. Obsidian Charmaw's enters-the-battlefield trigger destroys a nonbasic land (hitting Eldrazi Temple, Ugin's Labyrinth, or Urza's Saga) and leaves a 4/4 flier to pressure them. Tormod's Crypt exiles their graveyard after Malevolent Rumble fills it, which keeps Emrakul's cost reduction (based on card types in their graveyard) from kicking in. Practiced Offense and a couple Marauding Mako come out since this matchup is a pure race where disrupting their mana is more valuable than marginal pump effects. Keep the aggressive curve low and race before Emrakul or a seven-mana Devourer of Destiny comes online.

Eldrazi wants to assemble Urza's Saga into a free artifact and then ramp into Emrakul/Devourer. Malevolent Rumble fills their graveyard, which makes Emrakul cheaper, and Ancient Stirrings digs for colorless pieces. Surgical Extraction and Tormod's Crypt can strip their graveyard and buy time. Practiced Offense is too slow and clunky against a deck that ramps past our aggression curve, and Burning Inquiry gives them extra cards too, so trim both. Keep the low curve and Vengevine/Hollow One package intact since racing before Emrakul lands is still the primary plan. Lightning Bolt and cheap, fast threats like Blazing Rootwalla remain key to pressuring them early. Their Dismember kills most of our creatures, including Blazing Rootwalla and Hollow One, so spread out threats rather than relying on any one of them.

This matchup is a race against their ramp into Emrakul and Devourer of Destiny, so Rough (the sorcery half of Rough/Tumble) sweeps their small Eldrazi Spawn tokens and early creatures like Basking Broodscale for 2 damage. Tear (the {W} instant half of Wear/Tear) destroys Urza's Saga, which is an Enchantment Land, before it ticks to chapter III, and Wear (the instant half that destroys artifacts) kills a key artifact like Vexing Bauble or Blade of the Bloodchief if they're running a combo variant. Practiced Offense is too slow against their big colorless threats and Marauding Mako's clock is irrelevant if they just cast a 13/13. Keep the core looting/discard engine intact since you still need to race before they land Emrakul.