Shang waited in the middle of his territory.
He had already noticed that things were changing since even the two barriers he was keeping watch over had vanished.
If only one barrier had vanished, Shang might have tried to do something, but since both had vanished, he suspected that the Judgment Palace was finally giving up.
Shang had been isolated from the real frontlines for a thousand years, but the Judgment Palace's desperation couldn't be more obvious. After all, a Mage King had tried to kill him, which meant that the Lightning Manor was probably putting a lot of pressure on the Judgment Palace.
After seeing that the two barriers had vanished, Shang decided to check up on the other barriers around him.
That was when he saw the Attack Flag to the north.
This was the first non-hostile human contact in a thousand years, except for that little run-in with the Custodian.