Does anyone in Faerun know that Khelbens not who everyone thinks he is?
Steven Schend (who’s convinced no one can ever truly know Khelben until he truly knows and accepts himself, and he’s not ready to do that even after nine centuries) tells us: Actually, from my perspective, ONLY Danilo knows/understands that Khelben is not who he poses as. Cassandra is not all that close to her half-brother, and his training as a mage kept him even more at arms’ length as it was something he shared with their father that she couldn’t. As far as Cassandra’s concerned (though Elaine may have another interpretation of this, which is to be considered canonical as Cassandra’s her character), Khelben is her little brother who acts all the more mysterious because of the powers he wields….. Of others in Waterdeep, here’re my guesses as to who knows he’s not who he poses as (though they may not know exactly who he is): Kyriani (Agrivar), Mirt the Moneylender, Kitten, a few elves whose names escape me now, Maskar Wands (who actually may know the truth), Maaril & Hlanta Melshimb