Mortuary + Bolas's Citadel + Phyrexian Dreadnought + Cauldron of Essence

Mortuary

Bolas's Citadel

Phyrexian Dreadnought

Cauldron of Essence

How it works

1. Cast Phyrexian Dreadnought from the top of your library by paying 1 life.
2. When Phyrexian Dreadnought enters, it triggers, causing you to sacrifice it.
3. When Phyrexian Dreadnought dies, Mortuary and Cauldron of Essence trigger.
4. Resolve the Mortuary trigger, putting Phyrexian Dreadnought from your graveyard onto the top of your library.
5. Resolve the Cauldron of Essence trigger, causing you to gain 1 life and each opponent to lose 1 life.
6. Repeat.

This loop turns the top of your library into an endless revolving door for Phyrexian Dreadnought, bypassing traditional mana costs entirely through Bolas's Citadel. Because Bolas's Citadel allows you to play spells directly from the top of your library by paying life instead of mana, you can recast the Dreadnought for a mere 1 life each iteration. As the creature immediately sacrifices itself upon entering the battlefield, Mortuary steps in to catch it, seamlessly placing it right back onto the top of your library so the cycle can continue. Meanwhile, Cauldron of Essence acts as your win condition and sustenance, draining your opponents and padding your life total to fuel Bolas's Citadel's payments with every single death.