Jund Artifact Sacrifice floods the board with small creatures like Voldaren Epicure (1/1) and Greedy Freebooter (1/1), making Pyroclasm a strong sweeper against their wide, low-toughness board before Oni-Cult Anvil and Shrapnel Blast can scale up. Flowstone Infusion is cheap instant-speed removal that kills x/2s such as Voldaren Epicure, Greedy Freebooter and The Sackville-Bagginses, and it triggers prowess. Reckless Rage is cut since we don't want to expose our own small creatures to damage against a deck that already has Torch the Tower and Thoughtseize as disruption. Monstrous Rage is trimmed in favor of a sweeper and cheap removal since this matchup rewards board control over combat tricks. Weathered Runestone stays in the sideboard: this deck has no graveyard recursion for it to shut off.