Wrath of the Skies is a powerful sweeper against Mystic Forge Combo's artifact-heavy board, letting us pay enough energy to blow out Grim Monolith, Manifold Key, Giant's Boulder, and other low-cost artifacts they need to assemble their engine. Erode gives us additional cheap, instant-speed interaction to pick off Karn, the Great Creator or an early threat. Skyclave Apparition's exile trigger targets nonland, nontoken permanents with mana value 4 or less, which covers many of their engine pieces, including Karn, the Great Creator, but if Apparition later leaves the battlefield they get a 4/4 Illusion token back for an exiled Karn, so we cut the copies to make room for the sweeper. Flickerwisp is too narrow here since there's little upside to blinking their permanents, so it's cut for more proactive disruption.