This intricate loop transforms a simple sacrifice into a devastating engine by turning life gain into a self-sustaining casting requirement. When you sacrifice Oathsworn Vampire to Lord of the Forsaken, Pitiless Plunderer and Blood Artist both capitalize on the death; thanks to Teysa Karlov doubling those very death triggers, you net extra Treasure tokens and life. That life gain directly fulfills Oathsworn Vampire's condition to be cast from the graveyard, while Lord of the Forsaken's second ability conveniently filters your life payment into the exact mana you need alongside your Treasures to recast the vampire and start the cycle anew.