Fatal flaw
In fact, deducing that Richard is the son of the Third Heaven's Chosen, was not that difficult. After all, the alliance of the inferior beings works under the command of the Third Heaven's Chosen, and they were the ones who set the condition that they must not help the Azil tribe in their plight in any way. Here, it can be concluded that what is happening in the Azil tribe by order of the Third Heaven's Chosen.
And when they came here and saw Richard, this human child who had not yet reached the age of fifty, giving orders to dozens of human Martial Emperors, and all of them calling him Your Highness... Yes, they were not sure who he was, but with all these qualities who could he be other than the son of the Third Heaven's Chosen?