Sylas quickly found Aurion's main city. Or, rather, the Sylph pointed out the direction to him.
If nothing else, Aurion was quite resilient. He hadn't made a sound after being captured, and he also accepted his fate—in part. It was clear that he was looking for ways to remain alive.
Aurion knew that Nosphaleen was in Sylas' possession, but he had no idea in what capacity. He also wasn't fully aware just how much Nosphaleen had grown into her Mesmeryx abilities.
In Aurion's opinion, there was no method Sylas could have to bring Nosphaleen here, so the thought of being coerced into answering questions in this way couldn't have been further from his mind.
Nosphaleen wasn't an Overlord of her World, so it was impossible that she would be invited here. Without understanding that she was now one of Sylas' Contracts, there was no way he could guess how things would turn out when he led Sylas to his city.
