The Cogez family, sometimes adapted as Cozets, embodies wealthy 19th-century Flemish society. Patriarch Baas Cogez ascended from poverty to become a landowner and businessman, forging the family's nouveau riche standing. His rigid standards and dismissive view of the poor, rooted in his origins, fuel household tension. Baas displays abusive tendencies, especially towards his daughter Alois, forbidding her friendship with the impoverished protagonist and forcing her into boarding school. These actions contribute to Alois developing a delicate constitution, impliedly stress-induced. Baas frequently erupts in anger, such as when children break a vase during Alois's birthday, causing her to cower in fear.

Ellina Cogez, Alois's mother, offers a contrast as a reasonable and understanding figure. She advocates for her daughter against Baas's harshness, enduring verbal abuse for her interventions. Ellina recognizes Alois's emotional needs and attempts to mediate conflicts, though often ineffectively against her husband's stubbornness.

Alois Cogez emerges as a significant figure across adaptations. As a child, she forms a close bond with the protagonist despite class divisions, valuing his artistic talent and frequently requesting drawings. Her father forbids this friendship, leading to her isolation. During severe illness, receiving drawings sparks memories of happier times, aiding her recovery. In later life, depicted in a 1997 film adaptation, Alois becomes a nun. Visiting Antwerp Cathedral with orphans, she reflects on her childhood relationship. Her adult persona frames the narrative, recounting the tragic story and demonstrating how these events shaped her life path and spiritual choices.

A strong physical resemblance binds the family. Alois inherits her mother's facial features, eyes, and blonde hair, while also possessing a brownish hair tint from her father, visually reinforcing their interconnected relationships despite internal conflicts.