Rakdos Delirium relies heavily on graveyard value: Nethergoyf, Street Wraith's cycling, Detective's Phoenix's bestow-from-graveyard, and Stitcher's Supplier filling the yard. Grafdigger's Cage stops creature cards from entering the battlefield out of graveyards/libraries and prevents casting spells from the graveyard, hitting Detective's Phoenix's bestow-from-graveyard line directly. Soulless Jailer adds a redundant graveyard lock, also stopping permanent cards (like Nethergoyf's escape target reanimation) from reentering. We trim two Sowing Mycospawn and an Emrakul since this is a fast, disruptive matchup where cheap interaction against their graveyard plan matters more than big mana payoffs.