Josephine Mailstar, mother of Jeffrey Mailstar, heir to the knight-producing Mailstar lineage, hires sorceresses Lina Inverse and Naga the Serpent to train her son and elevate his standing for Royal Guard entry. She orchestrates staged scenarios where actors pose as adversaries for Jeffrey to defeat, aiming to build his confidence. Despite Jeffrey's physical traits—scrawny, clumsy, and prone to reckless blundering—Josephine staunchly believes in his capabilities and defends his perceived honor.

Josephine covertly shadows Jeffrey during training missions, her identity concealed by mask or bag. She intervenes violently, wielding a large mallet, against anyone criticizing or insulting her son, actions Jeffrey remains unaware of. Her protective measures include ambushing bandits who mock Jeffrey, though she is briefly incapacitated by a thrown rock. Her presence disrupts the training exercises, resulting in real bandits capturing her hired actors.

The narrative identifies Baron Goldias, operating under the alias Galda as an antagonist allied with warlord Rezo, as Josephine's husband and Jeffrey's father. During a confrontation, Josephine attacks Goldias with her mallet after he insults Jeffrey, leading to a family reunion. Following this resolution, Lina and Naga depart, leaving Josephine and her family to reconcile. Josephine's background and actions are confined to this episode.