The Murphy family didn't have any information about Chu Yunsheng's ability to make talismans. The only person who had seen it was Emily. However, she was terrified at the time; she didn't know what it was at all.
Therefore, when Chu Yunsheng slowly but powerfully approached the already broken glass door, and the patterns of a talisman formed quickly in the air, the vampires that surrounded him looked at the devil-like patterns in fear, not knowing what this undead was doing.
The man in heavy armor snorted in confusion, stood up abruptly, and walked forward two steps. He also didn't know what it was, but he had a bad feeling, so shouted, "Attack him at close range, don't let him cast the spell!"
Hearing what he said, those vampires "suddenly realized" that it was an evil spell. No wonder it looked so eerie and hideous.