Izzet Prowess aims to close the game quickly with Monastery Swiftspear and Dragon's Rage Channeler backed by cheap pump spells, so Brotherhood's End is your most impactful sideboard card — it sweeps their entire board of 1-toughness creatures at instant speed. Endurance comes in as a flash blocker with reach that also disrupts Dragon's Rage Channeler's delirium count, buying critical time to land Crashing Footfalls and stabilize. Mystical Dispute replaces Force of Negation as the more mana-efficient counter in this matchup, stopping Preordain, Expressive Iteration, and post-board Consign to Memory for a single blue mana. Force of Negation and Subtlety are trimmed because Force of Negation is weak against their low-to-the-ground noncreature spells and Subtlety's tempo bounce is insufficient against the volume of cheap threats they deploy. Your Leyline of the Guildpact and Leyline Binding package remains the backbone of your game plan, as protection from monocolored shuts off Lightning Bolt and Lava Dart targeting your Rhino tokens.