This elegant recursion loop centers on an exchange between Saffi Eriksdotter and Jackdaw Savior, where each brings the other right back from the brink. When you use Umbral Collar Zealot to sacrifice Jackdaw Savior, Saffi Eriksdotter’s waiting delayed trigger returns the Savior, while the Savior's own death trigger uses its lesser mana value interaction to pull Saffi Eriksdotter straight out of the graveyard and back onto the battlefield. Meanwhile, Umbral Collar Zealot doesn't just act as the necessary sacrifice outlet to kick off the cycle; its ability also lets you continuously surveil through your deck, turning the loop into an engine that generates infinite death, sacrifice, and entry triggers alongside endless card sorting.