The group finally descended to a decent height, but they were still high up in the sky to the point that they are not visible to those to the ground. Adrian stopped their descent at that height because that was the full range of the detection barrier that the royal mage of that kingdom has placed.
If they pass through the detection barrier, then the royal wizard will be informed of their location. They must be the ones that enter without being noticed. He now knows why Vayu and the Shade got detected because the whole barrier covered the kingdom. What intrigues Adrian is the fact that the barrier could cover the entire kingdom easily without any fluctuation.
"It seems that they either have large deposits of mana stones or they are sucking out the mana from every being in this kingdom slowly. If they did the latter, then they must be doing it to a degree that the people do not notice that their mana is being utilized." Adrian muttered as he started to think of a plan.