Mortuary + Falkenrath Noble + Bolas's Citadel + Fanatical Firebrand

Mortuary

Falkenrath Noble

Bolas's Citadel

Fanatical Firebrand

How it works

1. Activate Fanatical Firebrand by tapping it and sacrificing it.
2. When Fanatical Firebrand dies, Mortuary and Falkenrath Noble trigger.
3. Resolve the Mortuary trigger, putting Fanatical Firebrand from your graveyard onto the top of your library.
4. Resolve the Falkenrath Noble trigger, causing you to gain 1 life and target opponent to lose 1 life.
5. Resolve the Fanatical Firebrand ability.
6. Cast Fanatical Firebrand from the top of your library by paying 1 life.
7. Repeat.

This loop relies on Bolas's Citadel to cast creatures directly from the top of your library by paying life rather than mana, setting up a seamless recursion engine. When you sacrifice Fanatical Firebrand to deal damage, Mortuary instantly redirects it from your graveyard back to the top of your library so you can play it again. Meanwhile, Falkenrath Noble watches the carnage unfold, draining your opponents' life totals and padding your own life total to offset the cost of casting through Bolas's Citadel.