Boros Energy floods the board with cheap creatures (Ragavan, Ocelot Pride, Guide of Souls) and Wrath of the Skies lets us pay for enough energy to wipe their early board while leaving our bigger threats like Atraxa and Griselbrand alive. Celestial Purge exiles Ragavan or any red/black permanent cleanly, dodging their removal-light but aggressive plan. Force of Negation is weak here since their deck is creature-heavy and proactive rather than relying on key noncreature spells worth countering for free, and Spell Pierce is often blanked by Boromir's free-spell counter anyway. Watch out for Blood Moon turning our nonbasic lands into Mountains, so sequence Goryo's Vengeance plays around open mana when possible.