Claude Martha is Pierre Burnier's aunt and the great-aunt of Annette and Dani Burnier. Initially living in a separate village with her own children, she relocates to the Burnier household after Pierre's wife Francine dies, becoming a parental substitute who helps Pierre raise his children and manage domestic duties.

She serves as the family's moral compass, balancing rationality with empathy during conflicts. She acknowledges Lucien Morel accidentally caused Dani's leg injury and advocates for forgiveness, challenging Annette's enduring resentment by emphasizing the unintentional nature of the event. When Annette confesses to destroying Lucien's wooden horse, Claude Martha offers crucial emotional guidance focused on understanding and reconciliation rather than blame.

Claude Martha shows perceptiveness regarding interpersonal dynamics. After Dani finds a broken wooden toy ark outside their home, she links it to the biblical story of Noah, framing it as a tale of compassion and renewal, foreshadowing later efforts to heal fractured relationships. Her influence includes mediating tensions between Annette and Lucien, her advice helping Annette confront her own flaws and gradually move towards reconciliation.

Her background as a mother from another village shapes her pragmatic yet nurturing approach within the Burnier family. She maintains stability through daily routines and childcare, facilitating character development arcs centered on guilt and forgiveness.