Quirin's existence was an unexpected twist and nightmare for Sofia and Agda. Her existence seemed to confirm that the demon army was under her control. And with someone as smart as Quirin, destroying a kingdom is no longer difficult for a demon army that obediently listens to her orders.
In the worst-case scenario, Sofia thought they would only be fighting a demon army without a master, as she could not detect the Demon King's presence no matter how hard she tried. But Quirin's existence completely overturned her expectations. In an unimaginable situation, Sofia could only move her hands that were starting to feel cold.