Cavern Harpy + Vizkopa Guildmage + Oketra's Last Mercy

Cavern Harpy

Vizkopa Guildmage

Oketra's Last Mercy

How it works

1. Activate Vizkopa Guildmage by paying 1, causing each opponent to lose life whenever you gain life this turn.
2. Activate Cavern Harpy by paying 1 life, targeting any creature.
3. Repeat step 2 until you have one life.
4. Resolve all Cavern Harpy abilities, returning it from the battlefield to your hand.
5. Cast Oketra's Last Mercy by paying 1, causing your life total to become forty.
6. Vizkopa Guildmage triggers, causing each opponent to lose thirty-nine life.
7. Each opponent loses the game due to having zero or less life.