Gideon of the Trials + Axis of Mortality + Cavern Harpy

Gideon of the Trials

Axis of Mortality

Cavern Harpy

How it works

1. At the beginning of your upkeep, Axis of Mortality triggers.
2. Activate Cavern Harpy by paying 1 life.
3. Repeat step 2 until you have zero life.
4. Resolve the last Cavern Harpy trigger, returning it to your hand.
5. The remaining Cavern Harpy triggers fizzle.
6. Resolve the Axis of Mortality trigger, swapping your life total with an opponent.
7. The opponent loses the game due to having zero life.
8. You may repeat this on each of your turns.