Rocky and Karina had encountered giant magic capable of autonomously attacking targets on the Traceless Battlefield, known as the terrifying Magical Energy Storm.
Any target entering the Magical Energy Storm's range would suffer indiscriminate magical attacks. People once hoped this giant magic would halt the Demons' advance, and this served as a reminder to Rocky and Karina.
Although the Magical Energy Storm wasn't conjured by a Magic Circle but rather unleashed by dozens of top Archmages, the concept was evidently similar. The Magic Circle before them seemed identical, which meant that once within its range, the Circle would automatically activate and indiscriminately attack targets. This explained why there were Demons' skeletons surrounding the building and none dared approach, and it also explained why they were attacked.