Spirit Spider Technique

Charles was meditating with his eyes closed when a thought entered his mind: "Machu Picchu has completed its secondary maze-ification!"

He opened his eyes, smiling faintly. He felt it, the brand-new Machu Picchu Fortress, this ancient Beastman Kingdom stronghold was actually quite vast, after all, it was once claimed to be — 'the unbreachable Machu Picchu'.

It was built between two mountain peaks and was itself a vital passageway. At its peak, it had housed up to 270,000 troops, with hundreds of barracks, serving as the last bulwark protecting Strasbourg.

After the Sherlock Dynasty conquered this fortress through strategy, they preferred to set fire to Machu Picchu, turning the stronghold of the ancient Beastman Kingdom into ruins, precisely because it was too hard to attack. The Sherlock Dynasty had lost a lot of forces, and since they were in a hurry to capture Strasbourg, they didn't have enough troops to garrison.