This loop relies on the brilliant interaction between Isilu, Carrier of Twilight's front face (Eirdu, Carrier of Dawn) and Vizier of Remedies to neutralize the drawback of persist. When you sacrifice a creature to Woe Strider, Isilu's passive grants it persist, but Vizier of Remedies steps in to reduce the resulting -1/-1 counter to zero, allowing the creature to return to the battlefield fresh and ready to be sacrificed over and over again. Meanwhile, Eirdu, Carrier of Dawn provides crucial mana-discounting utility by giving your creature spells convoke, making it easy to weave this engine into a wider game plan.