They already told William everything they found, and there wasn't much to say anyway. That place was filled with tons of masters, lots of traps, and hellishly strong defences.
The moment they saw him using their spirit sense, they got shocked by the weird and intimidating shadow encompassing him. Yet he told them it was nothing, after listening to their description and thoughts about it.
"It can't be built overnight… This must have been built sooner after the expansion of the city," William muttered while knowing how hard this battle would be.
"Is there any weak spot there? A place we can use to get inside?" he could tell how dangerous that trench was. Trying to cross it was futile, and even if it was impossible, it'd take much time and lots of losses to do it.
He had to think of another way to deal with this, a weakness he could exploit no matter what.