Cassandra Thann

Lady Cassandra Thann is the daughter of Zelphar Arunsun. Zelphar came to Waterdeep with a young daughter in tow; eventually meets and marries Lhestyn {whose maiden name I don't recall}. Khelben Arunsun is her younger brother. Khelben Ravencloak Arunsun, that is. Khelben "Ravencloak" Arunsun is the grandson of Khelben "Blackstaff" Arunsun. The Ravencloak is now hanging on Oerth, after allowing his grandfather to take his place.