Mortuary + Altar of Dementia + Bolas's Citadel + Bontu's Monument

Mortuary

Altar of Dementia

Bolas's Citadel

Bontu's Monument

How it works

1. Activate Altar of Dementia by sacrificing a creature with mana value 1 or less.
2. When the creature dies, Mortuary triggers, putting the creature from your graveyard onto the top of your library.
3. Resolve the Altar of Dementia ability.
4. Cast the creature from the top of your library by paying 1 life.
5. Bontu's Monument triggers, causing you to gain 1 life and each opponent to lose 1 life.
6. Repeat.

This loop turns a low-cost creature into an unstoppable engine by exploiting the synergy between Altar of Dementia and Mortuary, which instantly recycles your sacrificed creature right back to the top of your library. Bolas's Citadel acts as the ultimate enabler, allowing you to bypass mana costs and recast that creature repeatedly using your life total instead. Meanwhile, Bontu's Monument not only reduces the black mana cost to make this loop seamless, but its triggered ability completely offsets the life you pay into Bolas's Citadel while draining your opponents out of the game.