Soul Echo + Axis of Mortality + Ethereal Champion

Soul Echo

Axis of Mortality

Ethereal Champion

How it works

1. At the beginning of your upkeep, Axis of Mortality triggers.
2. Activate Ethereal Champion by paying 1 life, preventing the next one damage that will be dealt to Ethereal Champion this turn.
3. Repeat step 2 until you have zero life.
4. Resolve the Axis of Mortality trigger, swapping your life total with an opponent.
5. The opponent loses the game due to having zero life.
6. You may repeat this on each of your turns.