A lot of people strongly believe gwynevere is priscilla mother(do to her size). So that make her half god(?) and half dragon. However I think a lot of places I've read said she was half human and dragon. ...I amazed at how much deep contemplation i put in to this lore...
Gwenevere was married to another god before she left Anor Londo and was replaced by Gwyndolin's illusion of her. Gwenevere was not Priscilla's father, and Seath is unconfirmed but has no evidence for the idea.