User blog comment:B214/Question and Answers 2/@comment-82.178.74.172-20140123213346/@comment-9339850-20140125014748

They never were, at least not exactly; LeFey wasn't introduced until Vali and his team had become more neutral, and she was probably the better person of them all. and Kuroka was mainly a trickster, and the only time she was "bad" was when she tried to get Koneko, essentially "rescue" or "save" her sister.