From what I can tell, there were three early Kestners ( Casners ) in Washington County/Smyth County.
John Kestner/Casnor, husband of Mary, and father of Henry, Leonard, and Jonas.His three children disappeared from the area in the early 1800s - I was told that at least one of them had moved to Tennessee.
John Kesner ( younger than the other John), husband of Rachel Weaver, and father of Elizabeth, Ward ( possibly John Ward) , Mary, Eleanor, David, Andrew, Charles Harden, Christianna, Philip, John C., and Jane.
Philip Kestner,husband of Elizabeth( Merchant? ) is my ancestor.He is roughly ten years younger than the second John Kesner.There is speculation that John and Philip were brothers, but there is no proof.Philip's son, John M. Kestner was born somewhere in Maryland - but there are very few usable records from that time period.
If Philip and John were brothers, then I would speculate that the older John was an Uncle.( there is no mention of any other children in the older John's Deeds in Smyth County ).
I was surprised when I found this forum - I didnt realize the Casner spelling had survived.I've seen Kesner, Kestner, and Kistner.