Skullius could hardly fathom what had possessed Theurien just now, and how Elita had known how to deal with it but he was relieved all the same. He imagined that perhaps what he had said to Theurien before bringing him here was too vague. He had wanted to surprise the man and give him hope.
Stylla was still alive, after all.
Skullius had simply wanted to show Theurien that Stylla was well, except for the fact that she didn't have a body and thus could only exist as a soul for now.
Because of the BoneTender, Stylla had been compromised and forced to travel with him as his aide. Yuyui had recounted to Skullius how she had managed to save Stylla, but stressed repeatedly that it had been a close call.