Mortuary + Atog + Bolas's Citadel + Ornithopter

Mortuary

Atog

Bolas's Citadel

Ornithopter

How it works

1. Activate Atog by sacrificing Ornithopter
2. When Ornithopter dies, Mortuary triggers, putting Ornithopter from your graveyard onto the top of your library.
3. Resolve the Atog ability.
4. Cast Ornithopter from the top of your library by paying 0 life.
5. Repeat.

This elegant engine transforms a humble construct into an infinite source of sacrifices, letting you cycle the same cheap artifact through your graveyard endlessly. Bolas's Citadel is the true linchpin of this operation, granting you the ability to cast spells directly from the top of your library while bypassing their mana costs with your life total. Since Ornithopter costs zero life to cast this way, it emerges from the top of your deck for free every single time Mortuary catches it on its way to the graveyard and neatly places it right back on top. From there, you simply feed the mechanical insect to Atog repeatedly, pumping its power to astronomical heights while generating an endless storm count and infinite death triggers.