Mortuary + Wild Cantor + Bolas's Citadel + Relic Vial

Mortuary

Wild Cantor

Bolas's Citadel

Relic Vial

How it works

1. Activate Wild Cantor by sacrificing it.
2. When Wild Cantor dies, Mortuary and Relic Vial trigger.
3. Resolve the Mortuary trigger, putting Wild Cantor from your graveyard onto the top of your library.
4. Resolve the Relic Vial trigger, causing you to gain 1 life and each opponent to lose 1 life.
5. Cast Wild Cantor from the top of your library by paying 1 life.
6. Repeat.

This ingenious loop turns a humble sacrifice into a relentless engine of life drain. With Bolas's Citadel granting you the ability to cast spells directly from the top of your library by paying life instead of mana, you can repeatedly cast Wild Cantor for a mere 1 life. As soon as you sacrifice Wild Cantor for mana, Mortuary instantly catches it on its way to the graveyard and places it right back on top of your library. Meanwhile, Relic Vial provides the crucial drain-and-gain payoff every time a creature dies, effortlessly offsetting the life you spend on Bolas's Citadel while draining your opponents out of the game.