Souhei's mother appears as a minor character primarily involved in a significant incident at her son's elementary school. Her son sustained an ear injury during an altercation where Yuki involuntarily transformed into a wolf-like state. This prompted a formal meeting in the principal's office, attended by Souhei's mother, Yuki's mother Hana, and school representatives. At this meeting, she displayed visible anger and concern over her son's injury.

Later, Souhei stated in his mother's presence that a wild animal caused his injury, deliberately shielding Yuki from blame. His mother's specific reaction to this account remains undocumented.

Limited information outside the school incident reveals she gave birth to a daughter prior to the events of a later major storm. Following this birth, her attention reportedly shifted significantly toward the new baby. Souhei confided in Yuki during that storm, expressing feelings of emotional neglect. He stated his belief that his mother "wouldn't care" about him anymore and voiced a desire to run away, highlighting his perception of a changed familial relationship after his sister's arrival.

Her narrative function is confined to the school incident and the implied familial context influencing Souhei's emotional state.