Mono-Black Midrange leans on Duress and Cabal Therapy to strip your combo pieces before pressuring you with Hypnotic Specter and Nantuko Shade, so Xantid Swarm lets you attack through their removal-light early turns while denying them a Duress or Cabal Therapy on your own attack step. Tormod's Crypt denies Cabal Therapy's flashback fuel and any other graveyard value they try to generate, and can proactively exile their yard before they set up. Tsabo's Web is weak since this deck runs little beyond Mishra's Factory and Wasteland as tapped-relevant lands, and Crystal Vein's sacrifice-for-mana ability isn't needed in a grindier matchup where you want to keep your land count up. Keep Tangle Wire and Defense Grid in, since both slow down their curve of efficient black creatures.