Jund Wildfire's whole plan revolves around artifacts like Ichor Wellspring, so Cast into the Fire's mode to exile target artifact is strong disruption against their card-draw engine, and its other mode can pick off 0/1 Eldrazi Spawn tokens. Relic of Progenitus exiles their graveyard, denying Eviscerator's Insight and other recursive value, though we keep the count modest since this matchup is still mostly a race. We trim slower cards like Inventor's Axe and excess Chain Lightning since their removal suite (Cast Down) can pick off our equipped creature anyway.