Lydia Glasher is Grandcourt's former lover. She left her husband for Grandcourt and has four children with him, including a son who will take Grandcourt's name and who stands to inherit all of Grandcourt's wealth someday. Lydia is a pretty pitiful figure – she doesn't have a lot of options, and her whole wellbeing depends on whether or not Grandcourt still feels charitable towards her. She feels like she's his rightful wife and has no problem tormenting Gwendolen if it means helping herself out. In a way it's easy to hate her, but if we spend a minute in her shoes, we can kind of understand where she's coming from.