Cerberus was right. Roy either did not attack, or he had to teach these whip demons a profound lesson.
These mutated demons really made him feel vexed. They did not know respect nor fear, and their hunting instincts far exceeded their rationality. If he had not encountered such demons, he would have let them be. But now, not only did he encounter them, but they also blocked his path. This was their sin.
There were tens of millions of them, and it was impossible for Roy to use magic power to fight them from beginning to end, so his method should naturally be sharper.
The plague viruses that Roy used now did not mean that he carried these viruses in his body but that he could use magic power to transform them.