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

Leonardo, Sewer Samurai

Solemnity

Ashnod's Altar

Crookshank Kobolds

How it works

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

This clever loop relies on Crookshank Kobolds—which costs zero mana to cast—as a virtually free sacrifice fodder for Ashnod's Altar to generate infinite colorless mana and endless triggers. Ordinarily, Leonardo, Sewer Samurai would place a finality counter on the Kobolds when casting them from the graveyard on your turn, exiling them the moment they hit the graveyard again and ending the loop. However, Solemnity completely shuts down those counters from ever being placed, allowing you to sacrifice, recast, and repeat the entire sequence indefinitely without the Kobolds ever leaving your graveyard's reach.