Going back a few moments in the past, shortly after Rean, Celis, and Tobao finished dealing with the two exposed puppets, Rean secretly contacted Tobao again through the RC. At that moment, Rean informed Tobao that there was still one more puppet hidden among the surviving Array Masters.
Truth be told, Rean had lied earlier when he claimed he identified the puppets because of their reactions.
In reality, the method he used was far, far simpler.
He looked at the killing intent.
Being able to see killing intent was an incredibly convenient ability in situations like this. Since those Array Masters were merely puppets being controlled, there had to be a sentient mind behind them somewhere else. Even if the one controlling the bodies wasn't physically present there, the moment they formed the intention to kill someone, that murderous intent would naturally manifest itself through the puppet.
The instant the array activated, the puppets had already prepared themselves for battle.
