Mordant's sudden questions about appraisals didn't catch Walker off guard at all. He had expected that one of the dragons would be asking him more questions at some point. There was a sure chance that the dragon blood that had been passed down in to whatever ancient race this was would have some effect on their history.
However, Walker also understood that this was just part of things. If there were dragon ruins somewhere under the sands, it would be imperative that the dragons found it. The undead in the ruins the army was marching to might hide secrets that involved this. It was just something everyone understood.
The Fel angels were paying close attention to the fact that Mordant had begun to carefully listen to every single all around appraisal. This had made them sure that the dragons might share some of their love for researching. They didn't have enough information to fully understand why Mordant was curious about all of this.