Grixis Reanimator wants to discard Archon of Cruelty with Faithless Looting or mill it with Thought Scour, then bring it back with Unearth or Persist for a huge tempo swing, and Soulless Jailer's static ability shuts off any permanent card entering the battlefield from a graveyard, stopping Unearth and Persist cold. Thoughtseize strips their reanimation spell or Fatal Push before they can execute the plan, while Fatal Push itself answers Psychic Frog and Abhorrent Oculus before those threats take over. Cut your own graveyard-filling cards like Malevolent Rumble and Dredger's Insight since you don't want to hand them extra graveyard fuel or dilute your disruption. Your maindeck Endurance is also strong here, putting their graveyard on the bottom of their library and denying every reanimation target at once.