No dude, that's what happened when grey doesn't existed. All adopted child is there because they're ALWAYS there in the story, wheter grey existed or not. Remember in previous chapter there's a glimpse vision of a timeline where grey doesn't exist to save them. one of grey adopted child (ars or something, i forget the name) that supposed to be the MC in the game defeated the Hero and ask him "did you kill someone named Aria?". He refers to this instance, it turns out Aria doesn't get murdered, she killed herself. The Hero doesn't kill her.