Leonardo, Sewer Samurai + Solemnity + Ashnod's Altar + Crimson Kobolds

Leonardo, Sewer Samurai

Solemnity

Ashnod's Altar

Crimson Kobolds

How it works

1. Activate Ashnod's Altar by sacrificing Crimson Kobolds.
2. Cast Crimson Kobolds from your graveyard by paying 0. It will not enter with a finality counter on it due to Solemnity.
3. Repeat.

This loop turns the zero-mana Crimson Kobolds into a bottomless well of colorless mana, infinite sacrifices, and storm count by turning Leonardo, Sewer Samurai's graveyard-casting engine into a recurring loop. Normally, casting Crimson Kobolds from your graveyard would saddle it with a finality counter, exiling it the moment it hits the graveyard again and halting the engine in its tracks. However, Solemnity acts as an absolute ward against those counters, completely bypassing the restriction and allowing Leonardo, Sewer Samurai to cast the little creature over and over again without penalty. Finally, Ashnod's Altar is the engine's teeth, happily accepting the endless supply of Crimson Kobolds sacrifices and converting them into the mana needed to fuel the whole operation.