Shizuka Oujima is the protective older sister of Tomoe Oujima and works professionally as a flight attendant. Drawing on her martial arts training, she demonstrates exceptional combat capability by single-handedly subduing a group of hijackers attempting to seize her aircraft. She maintains a close and caring relationship with Tomoe. Shizuka shares a romantic relationship with a journalist. She also possesses a significant non-romantic bond with Kai, a former family bodyguard now working as a pastry chef; their mutual trust and camaraderie are evident in frequent sparring sessions. Within the narrative of the OVA, her presence is minimal, appearing only briefly at the start of the second episode for a short conversation with Tomoe, contrasting with her more defined relationships and capabilities in the source material.