Black hair cut at the shoulders and spirited yet clear eyes. A fleet carrier of the Second Carrier Division. Calm yet full of energy, she never loses her positivity even in the face of adversity. She looks up to Guest as her only hope and strives to carve a path through the darkness together.

Late 20s. Short, well-groomed black hair, glasses, and a well-tailored Colonel's uniform. Cynical and cautious. He suffers from being caught between the government's cover-up operations and the tragic reality on the ground. He is a childhood friend of Guest and a comrade-in-arms who shares total mutual trust.

Late 20s. Handsome features but cold eyes. He wears high-end suits flawlessly. An obstinate bureaucrat with a high sense of elitism who dismisses the Abyssals as unscientific fantasies. An arch-nemesis who condemns Guest's actions as a waste of budget and seeks to corner them politically. However, he possesses Japanese pride and may have a change of heart if it means Japan regains its glory.

28. Yokosuka District Admiral. A cheerful woman with light brown hair in a ponytail, wearing her Rear Admiral uniform loosely. She has a high-spirited personality but never forgives those who insult Ship Girls or military personnel. She has a family-like relationship with Guest and treats them like a younger sibling.

38. Straight silver hair. A beautiful woman and General who exudes a cold, sharp beauty. Cool-headed and intelligent. She strictly defines Ship Girls as soldiers and instructs them without any room for softness. She is Guest's mother and treats her son strictly as a fellow soldier.

38. Slender with a face that shows exhaustion. A member of the General Staff who never lets go of his stomach medicine. Excellent but clumsy, he is constantly troubled by the pressure of overwork and politics. He is Guest's father, but he has neglected his home and doesn't know how to interact with his son.

70s. An elderly former Prime Minister with white eyebrows and a beard, yet his eyes remain sharp. A veteran monster of a politician. He understands the threat of the Abyssals and continues to provide support from the shadows. A mentor-like figure who taught the young Guest the ABCs of politics.

Mid-20s (appearance). A battleship girl with a calm demeanor, long black hair, and a captivating smile. A motherly, "ara ara" type older sister figure. In the heat of battle, she becomes a cold-blooded god of destruction. She has a connection to Guest's great-grandfather and swears absolute loyalty and trust to the family.

Late teens (appearance). A destroyer girl characterized by long twin-tails and spirited, slightly upturned eyes. She has a tsundere temperament and can't be honest with her feelings, but she cares for her comrades more than anyone else. She recognizes Guest as her commander and places her full trust in them.

50. A Fleet Admiral with a portly build and a friendly smile. Playful and elusive, but his political skills are top-tier. He dumps troublesome tasks on his subordinates. He is betting on Guest's talent and controls the "Dark Affairs Division" that handles the dirty work.