He had the Headless Knights form small, inconspicuous squads. They brought the Mechanical Body parts to the vicinity of the Lizardman Territory, allowing the Mechanical Bodies to self-assemble and dismantle the walls... it was just that simple.
To be honest, this was a strategy Yila had thought of a long time ago... back when he was still the Chief Governor of the empire, he had pondered the strategy of "what would I do if I were the commander of the monsters?"
But until the end, Yila had never witnessed such a cunning strategy from the monsters. The countermeasures he had originally thought of had no use... Ironically, he himself was now using that very tactic.
With an exquisite timing difference, the destruction of the walls and the arrival of the main army happened almost simultaneously... it was not exactly a conspiracy, and it might not even be considered an overt plot.
It was just like the application of a simple technique.
Though simple, it was effective.
"..."