Someone whispered those words. In response to that voice, Archer of Red grabbed her bow. She still hadn’t realized that the whispers of the evil spirits had turned into her own words.
Low level evil spirits could only repeat the same whispers. They shouldn’t have even have had the intelligence to change their words according to the situation.
...
Those children were what brought the Servant Assassin of Black into existence… in other words, they were like the foundation of existence known as ‘Jack the Ripper’. Naturally, they were already dead.
Even so, if they were left alone, they might have possessed some powerless human. In that case, it was highly possible that a Jack the Ripper with a living human body would have appeared.
Of course, they were low-class evil spirits. The most they would have been able to do was give someone the urge to commit murder, and they would have lacked any supernatural powers.