Jeskai Ephemerate is a card-advantage deck built around enters-the-battlefield creatures like Mulldrifter, Augur of Bolas, and Archaeomancer, which Ephemerate can blink for extra value, while Murmuring Mystic turns their instants and sorceries into Bird tokens. Tithing Blade forces them to sacrifice a creature, which is painful against that creature base, though they choose which one, so Bird tokens can soak it up. Cut Down cleanly kills Archaeomancer, Augur of Bolas, and Mulldrifter, but Murmuring Mystic is too big for it. Hydroblast counters Skred, their main removal spell. Dust to Dust is not worth bringing in, since their only artifacts are a few copies of Bender's Waterskin and you would end up exiling your own artifacts. Giant's Boulder is too slow against their efficient card-advantage engine and interaction (Skred, Counterspell), so cut it for proactive disruption. Watch out for Counterspell backing up their value creatures, and try to play around open blue mana when possible.