Lady Ophelia Balassar
Lady Balassar is the wife of Fjornin Balassar and the mother of Evander Balassar. She's rarely seen as she seldom leaves the family's manor, and is implied to have severe depression, possibly postpartum, since having Evander. Her mental illness and overall persona is kept under wraps from the public eye, however we're given several hints throughout the series that she has close relationships with both her husband and son.
Ophelia drowns herself in the Obsidian during the trilogy, and several previous suicide attempts are alluded to before this.