While they left, Alex used Void Walk to return to the platform where he had found the children earlier. The reason why he had come back was because he wanted to use the Warden of the Rift spell again, he wasn't satisfied with the strength of the people he had met in this place.
He was certain there were more members of the Dark Union outside and stronger ones too. For instance, the guy with the shadow element who had tried to invite Alex to join the Dark Union; he didn't find him here.
Alex was sure there was still someone else behind that person who had tried to invite him, since the one controlling the members of the Dark Union in Balon City would probably not come to him personally, since it would be too risky.
Could it be that they somehow knew that he was coming and had left in advance?
Alex shook his head at the thought of this. They couldn't know that he was coming since he hadn't told anyone, it must have been a coincidence.
