Boros Energy wants to curve out with cheap threats like Ocelot Pride, Guide of Souls, and Ragavan, Nimble Pilferer, so Chalice of the Void set to X=1 blanks most of their one-drops and even a dashed Ragavan on cast. Thought-Knot Seer strips their best remaining card from hand while blocking the small creatures all day, and Dismember cleanly kills anything at 5 toughness or less (Ragavan, Guide of Souls, Voice of Victory, Seasoned Pyromancer) though it won't touch bigger late threats. Cut the clunkiest top-end (Ulamog, extra Emrakul copies) and the slow Drowner of Truth since this matchup is about surviving the early beatdown and stabilizing, not grinding a long game.