UBG is a reanimator deck using Animate Dead, Reanimate, and Shallow Grave to cheat Griselbrand, Atraxa, and Archon of Cruelty out of the graveyard, so Leyline of the Void can be started in play from our opening hand to shut off their entire graveyard-based plan before it starts. We cut Call Forth the Tempest since its triple-red cost is the most awkward of our cascade spells to cast on curve and this matchup is decided more by disrupting their reanimation targets than by board-wiping small creatures. Leyline also incidentally shuts off their Faithless Looting flashback and any Unmask-into-discard synergies tied to the graveyard. Keep pressure on with our own cascade spells since they still need to find a way to reanimate through our hate piece.