Xathrid Demon + Malignus + Archfiend of Despair

Xathrid Demon

Malignus

Archfiend of Despair

How it works

1. At the beginning of your upkeep, Xathrid Demon triggers, causing you to sacrifice Malignus and causing each opponent to lose life equal to Malignus's power.
2. At the beginning of your end step, Archfiend of Despair triggers, causing each opponent to lose life equal to the amount of life they lost this turn.
3. Each opponent loses the game due to having zero or less life.