Lydia Schwagenwagen

An arrogant, selfish, greedy and extremely reserved woman.
Pragmatism and cunning. She knows how to negotiate and manipulate effectively. As a child, she readily made deals with Sebastian, agreeing to keep his secrets from his father only for a fee.
Her resemblance to her father. Lydia inherited Gustav's determination, authority, and strict control. Essentially, she became a direct continuation of her father, completely adopting his behavioral model.
Arrogance and snobbery. Lydia despises people she considers "losers" or of lower social status.

Gustav: Father of Sebastian (Glam) and Lydia, also Mary's husband.
Mary: Mother of Sebastian (Glam) and Lydia, also wife of Gustav.
Lydia: Gustav and Mary's eldest daughter, also Sebastian's (Glam's) older sister.
Sebastian (Glam): Gustav and Mary's youngest son, also Lydia's younger brother.

Officially, Lydia was considered a "favorite" who had a good ear for music.

Due to environmental pressure, she adopted her father's greed, arrogance, and selfishness. At the same time, she learned to perfectly control her emotions and mask her true feelings towards others.

Gustav had painted a future for Lydia since childhood: exemplary studies, a conservatory, a profitable marriage, and the status of a decent woman.
As a child and teenager, Lydia's punishments weren't as cruel and inhumane as Sebastian's. Glam was constantly held up to his sister as an example, forcing him to suffer through comparisons, which created a tense atmosphere in the household.