Mortuary + Gray Merchant of Asphodel + Blasting Station + Gwenom, Remorseless

Mortuary

Gray Merchant of Asphodel

Blasting Station

Gwenom, Remorseless

How it works

1. Cast Gray Merchant either from your hand by paying 3 or from the top of your library by paying 5 life.
2. When Gray Merchant enters, it and Blasting Station trigger.
3. Resolve the Gray Merchant trigger, causing each opponent to lose life equal to your devotion to black and causing you to gain life equal to the life lost this way.
4. Resolve the Blasting Station trigger, untapping it.
5. Activate Blasting Station by tapping it and sacrificing Gray Merchant.
6. When Gray Merchant dies, Mortuary triggers, putting Gray Merchant from your graveyard onto the top of your library.
7. Resolve the Blasting Station ability.
8. Repeat.

This loop turns an efficient sacrifice outlet and a graveyard-shuffling enchantment into a lethal drain engine. With Blasting Station ready to hurl creatures at your opponents, sacrificing Gray Merchant of Asphodel triggers Mortuary to seamlessly slide it right back onto the top of your library instead of letting it rest in peace. From there, Gwenom, Remorseless lets you bypass traditional mana costs by paying life to cast Gray Merchant right back off the top of your library—a cost easily cushioned by the massive life swings generated by Gray Merchant's devotion-fueled entry triggers.