The fact that Old Folks' Campfire wasn't a normal Territory hadn't been lost to Skullius since the first time he had to endure all the attacks it held. The moment he saw that it had living beings within it, created out of the Ode's power, he had turned wary.
Even with his prior knowledge, before being influenced by the WILLS, Skullius could already somewhat differentiate the Tiers of Territories, which were distinguished by how many living creatures were within it. This difference he had noticed early on was with the Great Mane Mountain Ape Azila's Territory, which had the flying Cluster Flies, and the Territory of the Grinning Jester Fox, which didn't have any living beings at all.
His more recent intel pointed towards how Rayn's Territory had held within it an entire city of humans praising a moon.