Mortuary + Bolas's Citadel + Fanatical Firebrand + Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel

Mortuary

Bolas's Citadel

Fanatical Firebrand

Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel

How it works

1. Activate Fanatical Firebrand by tapping and sacrificing it.
2. When Fanatical Firebrand dies, Mortuary and Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel trigger.
3. Resolve the Mortuary trigger, putting Fanatical Firebrand from your graveyard onto the top of your library.
4. Resolve the Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel 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 creates an endless cycle of recycling and sacrificing by combining the top-deck manipulation of Bolas's Citadel with the recursive library placement of Mortuary. When you sacrifice Fanatical Firebrand to its own ability, Mortuary catches it on its way to the graveyard and immediately places it right back onto the top of your library. From there, Bolas's Citadel lets you cast it straight off the top for a mere 1 life instead of its mana cost, feeding a continuous loop. Meanwhile, Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel watches every single death and sacrifice happen, turning the revolving door of creatures into an unstoppable torrent of damage, lifegain, and opponent life loss.