This clever loop turns Glen Elendra Archmage into an endlessly recurring counterspell engine, fueled by the sacrifice outlet Bartolomé del Presidio. Each time you sacrifice the Archmage, its persist ability normally brings it back with a -1/-1 counter, permanently locking it out of future uses—but that's where Thran Vigil steps in. Because the Archmage leaves your graveyard when persist resolves, Thran Vigil's passive trigger catches the event and places a +1/+1 counter on a creature. Thanks to Magic's state-based actions, the +1/+1 counter and the -1/+1 counter immediately annihilate each other, leaving the Archmage completely clean and ready to persist all over again.