Berta, called Bertha, commands the guard forces of Evermore kingdom, tasked with defending its borders against threats like the Black Banner army’s invasion. Her striking resemblance to Saki—Yu’s adoptive sister—draws his attention, though the likeness remains an unexamined curiosity. As captain, she engages in critical battles and strategic operations to safeguard Evermore, though pivotal actions, such as a decisive clash credited to her leadership, unfold beyond direct narration. Her background, origins, and personal motivations remain obscured, with no elaboration on her past or aspirations outside military service. Interactions with others center on her authoritative role, maintaining a focus on duty over personal bonds. Beyond her primary storyline, no additional accounts explore her presence in other official narratives.