Afterlife from the Loam
Reanimation spells that pull from every graveyard have traditionally scaled with the table but not with the clock: the more players you steal from, the more mana you sink, and the payoff arrives late. Delve is the lever this design pulls to break that pattern. The printed cost sits at eight, but your own graveyard is a resource that pays it down, so the more the game has churned (fetches cracked, spells cast, creatures traded) the closer this drifts toward castable in the midgame rather than the endgame. That creates a genuine tension: every creature card you exile to shave the cost is a body you are not reanimating and not leaving as a target for later. Fuel and payload draw from the same well.
The Zombie rider is the quiet half of the design. Turning every stolen creature into a Zombie in addition to its types is not a flavor throwaway; it stitches a pile of unrelated bodies (whatever happened to die around the table) into a coherent tribe the moment they arrive under your control, so the theft doubles as tribal support for whatever count-matters or lord effects you have waiting. Mass steal-and-convert effects are rare in mono-black because black usually pays for graveyard theft in life or in card disadvantage. Here the payment is the graveyard itself, and the conversion means the board you assemble across every opponent's dead is not just larger than theirs but unified under your control the instant it lands.

