Leonardo, Sewer Samurai + Solemnity + Arcbound Ravager + Ornithopter

Leonardo, Sewer Samurai

Solemnity

Arcbound Ravager

Ornithopter

How it works

1. Activate Arcbound Ravager by sacrificing Ornithopter.
2. Cast Ornithopter from your graveyard by paying 0. It will not enter with a finality counter on it due to Solemnity.
3. Repeat.

This clever loop turns the graveyard into a free, infinitely recurring workshop by leveraging Leonardo, Sewer Samurai to cast Ornithopter directly from the graveyard for zero mana. Solemnity is the linchpin that protects the entire engine, gracefully overriding Leonardo's finality counters and ensuring the thopter never gets permanently exiled. Meanwhile, Arcbound Ravager provides both the sacrifice outlet to send the thopter back to the graveyard and a permanent place to pile up infinite +1/+1 counters.