@campbella The most detail we've ever been given about the fate of Dahlia's mother is this bit from late in Vol 2:
Dahlia: "I hereby confess, um... When my mother was pregnant with me, she returned to her family home, where she gave birth to me, and then my younger brother a year later."
Volf: "I wonder if she felt more at ease there. It's a common story among nobles - you hear of men's wives going back to their families all the time."
Dahlia: "I expect so. It seems she loved her noble home so much that she decided to divorce my father, give me to him, and marry the man who fathered my brother instead. That's why I never knew her."
Volf: "I'm sorry, Dahlia. I didn't mean to bring up any painful memories."
Dahlia: "Don't worry. It isn't painful. I just thought I'd rather tell you myself than have you hear it from someone else someday. Any ties between my mother and I were severed a long, long time ago. And she's gone, in any case. Same as Father."
Now that exchange certainly does seem to imply that Dahlia's mother is dead. But in a series that doesn't avoid outright saying when someone's dead, Dahlia sticking to euphemisms with regards to her mother also hints that she may not be sure... or she may know she's still alive, but firmly out of Dahlia's life.
Indeed, the only direct reference I could find to Dahlia's mother being dead in the entire series to date was Barbara assuming that was the case when Dahlia told her "I don't have a mother."
So in short; Don't count Dahlia's mother amongst the dead quite yet!
