Evan had already suspected that the Hero in Tarse was a Royal.
Why?
Take a look at the other Heroes he already knew of.
Abigail, Laurene, and David, the First, Fourth, and Fifth respectively, were all Royals of their own nations.
From that alone, Evan had guessed there was a strong possibility that Tarse's Hero would be a Royal as well, a suspicion that was confirmed when he arrived at the Sandfire Palace last year and sensed lingering traces of a Hero Authority.
He wasn't sure what the Hero had done with their Authority, but whatever it was had been significant enough to leave remnants that persisted until Laurene arrived months later and sensed them too.
When Evan had visited the Sandfire Palace last year before the FCD incident, all the Royals had been present except for three, so he'd narrowed his suspicions to that trio.
And one of those three was the woman now standing before him, the First Princess of Tarse, Bianca Eileen Austin.
