The saddest character death for me was Penelope Aldaya in The Shadow of The Wind. Her death was horrific, there’s no question of that, but what made it worse was that her family stood by and allowed it to happen as a macabre punishment for conceiving a child out of marriage and admittedly unwittingly with her half brother (children being punished for the crimes of the father). The death of the mother and child is crushing and the whole novel stems from this.
The most satisfying character death? Bellatrix Lestrange. “Get away from my daughter you bitch!” Go Mrs. Weasley!!!