Mortuary + Daxos, Blessed by the Sun + Wild Cantor + Bolas's Citadel

Mortuary

Daxos, Blessed by the Sun

Wild Cantor

Bolas's Citadel

How it works

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

This ingenious loop transforms Bolas's Citadel into a life-positive engine by letting you cast Wild Cantor straight from the top of your library for a mere 1 life instead of its mana cost. The moment Wild Cantor dies to its own sacrifice ability, Mortuary immediately intercepts it, placing the creature right back on top of your library to keep the chain alive. Meanwhile, Daxos, Blessed by the Sun watches the entire process unfold, generating a net gain of life on both ends of the creature's journey so that your life total actually increases with every single iteration.