Workhorse + Light of Promise + Emiel the Blessed + Gray Merchant of Asphodel

Workhorse

Light of Promise

Emiel the Blessed

Gray Merchant of Asphodel

How it works

1. Activate Emiel the Blessed by paying 3, blinking Gray Merchant of Asphodel.
2. When Gray Merchant of Asphodel enters the battlefield, it triggers, causing each opponent to lose life equal to your devotion to black, and causing you to gain that much life.
3. Workhorse triggers, putting at least three +1/+1 counters on itself.
4. Activate Workhorse three times by removing three +1/+1 counters from it, adding CCC.
5. Repeat.
6. If your devotion to black is at least four, this combo nets infinite +1/+1 counters on Workhorse and colorless mana.

This loop creates an engine of continuous rebirth by leveraging Emiel the Blessed to repeatedly blink Gray Merchant of Asphodel, whose enter-the-battlefield trigger drains our opponents and pads our life total. That newly gained life feeds Light of Promise, which supercharges Workhorse with a wealth of fresh +1/+1 counters each time our life total climbs. In turn, Workhorse can immediately sacrifice those very same counters for the colorless mana needed to fund Emiel the Blessed's blinking activation cost, sustaining the cycle indefinitely.