Spy Combo wants to flood its graveyard and reanimate huge threats via Dread Return, so Relic of Progenitus both disrupts that plan and denies Balustrade Spy's graveyard fuel. Pyroblast and Red Elemental Blast have no legal targets since the opponent's list is entirely green/black with no blue spells or permanents. We are the faster, more linear deck here, so minimal changes are needed beyond adding graveyard hate; keep the burn suite intact to race before their ramp creatures take over.