Previous chapter the sealed god said he had other plans, and when Urza had just awakened as controlled evil king she said someone had done it and gave the order, I believe the sealed god was able to communicate with someone that followed him after all that time or it was one of his plans to revive and he influenced the right people above ground to act in his favor, the fall o fthe demon kingdom, human territories and dragon empire would have caused too much chaos for the gods, giving him the right moment to break the 8 sealing stones at the same moment, revive and control his subordinates directly.
MC cutting the bindings and lowering its power by changing the sealed body parts made the hostiles regain their sanity.