Mortuary + Altar of Dementia + Memnite + Gwenom, Remorseless

Mortuary

Altar of Dementia

Memnite

Gwenom, Remorseless

How it works

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

This loop relies on Altar of Dementia to continually sacrifice Memnite, fueling an endless chain of creature sacrifices, enters-the-battlefield, and leave-the-battlefield triggers while milling out your opponents. Because Memnite costs zero mana, Mortuary catches it the moment it hits the graveyard and neatly places it right back on top of your library. From there, Gwenom, Remorseless bridges the gap by letting you look at and cast spells from the top of your library, allowing you to replay Memnite for zero life instead of its mana cost and instantly restart the cycle.