Claim the Firstborn is weak since Izzet Phoenix runs few relevant creatures worth stealing, and Bloodtithe Harvester's removal mode is often too slow against a combo-oriented graveyard deck. Ghost Vacuum is a key sideboard card here, directly exiling Arclight Phoenix from their graveyard to shut off its recursion trigger. The Legend of Roku provides card advantage and a resilient late threat that outlasts their burn spells like Fiery Impulse and Lightning Axe. Race aggressively with Mayhem Devil and Fable of the Mirror-Breaker while using Ghost Vacuum proactively before they can chain Arclight Phoenix returns.