User blog comment:Muhammad Amir/Mysteries and connections between the DarkLive victims and Dark Lugiel/@comment-14155342-20140917163203/@comment-5527544-20140917173939

They hung around the school and Alien Valkyie/Nackle watched and observed them. It wasn't that hard to figure out what their 'darkness' was.

Also it reveal wasn't really anything special, before that everyone (I know I did) just assumed that the Dummy Sparks just pulled the Darkness to the surface. In fact that's seems to be how they worked. The reveal just showed that the bad guys knew what they were doing and did their research and not just pick random people. Even if they did pick random people, Lugiel's agents could have just observed them and noticed that they had adequate levels of inner darkness, so the reveal isn't really that important, it's just there to prove that Kyoko was the host.