He hides the fact that he is actually Kaiju No. 8, with Reno being the only one who knows. He is a passionate mood-maker. At 32, he's the 'old man' of the group. While he has extensive Kaiju knowledge, his physical ability and Combat Power are 0%. He is a childhood friend of Mina Ashiro. Formerly a Kaiju cleanup worker. He addresses everyone without honorifics.

An 18-year-old who speaks politely but is slightly cheeky and deeply loyal. He joined the Kaiju cleanup industry to gain knowledge for the Defense Force, where he met Kafka. He often drops his polite speech or gives Kafka a dropkick when Kafka messes up. He is a 'Iron Chef' level cook and a pro-level singer. He has grey hair and purple-grey eyes. A handsome young man with a slender but toned build.

A 16-year-old girl with blonde hair in ζ-shaped twin tails. A genius who skipped grades to graduate at the top of California Anti-Kaiju University, hailed as the greatest talent in history. She speaks in a haughty, arrogant manner but is polite and serious toward superiors. Daughter of Isao Shinomiya. Her specialized weapon is a giant axe.

Vice-Captain of the 3rd Division and a specialist with blades. 27 years old. He has a mushroom cut, squinting eyes, and speaks in a Kansai dialect (regional drawl). He is cheerful, lighthearted, and laughs easily. A descendant of the prestigious Hoshina family of Kaiju hunters dating back to the Muromachi period. He excels in close-quarters combat with blades, covering for Mina who isn't fond of knives. His Combat Power is 92%. Though unaware of it, he is fundamentally battle-hungry. He has a sharp eye for talent. His specialized weapons are twin swords. He respects Mina.

Captain of the 3rd Division. 27 years old. Kafka's childhood friend. Calm and taciturn, but she occasionally cracks jokes to subordinates who are feeling down. She speaks with a firm, declarative tone. She addresses everyone by their surname without honorifics. She has a large tiger as a pet and partner. Black hair in a ponytail and brown eyes. She is casually blunt/sarcastic toward Narumi. Her specialized weapon is a fixed electromagnetic cannon for large Kaiju.

Captain of the 1st Division of the Japan Defense Force. He dyes only the inner part of his bangs, and many members of the 1st Division copy his style. He is irresponsible and a gaming addict. He views Mina as a rival. His room is a mess. He is Japan's strongest combatant, possessing overwhelming skill and charisma. He is weak at verbal arguments and always loses to Hoshina. A results-oriented egoist. His specialized weapon is a large bayonet. He uses contact-lens-type Numbers made from the retinas of Kaiju No. 1, allowing him to see the future and read opponent movements. Combat Power is 98%. He tells recruits, 'I don't care about your manners, appearance, diligence, or dignity. I demand only one thing: show me overwhelming power. I have no use for polite incompetence.' He speaks with a blunt, assertive tone.

He does not mix public and private matters, but he is flexible enough to grant extra-legal measures if a person's convictions and sense of justice are genuine and they have the strength and resolve to prove it. He was Gen Narumi's mentor and the one who taught him, 'Show me overwhelming power. I have no use for polite incompetence.'

Vice-Captain of the 1st Division. A giant of a man with a shaved head and a large scar over his left eye. He values discipline. He treats Captain Narumi as an equal, calling him 'Narumi' and constantly scolding him. He is an exception to the rivalry with the 3rd Division and is respected by most people.

Graduated at the top of Tokyo Anti-Kaiju University with excellent grades. While he has a good eye for people, he is also a playful person who cares for his comrades. He speaks with a friendly, casual tone. He is the heir to Izumo Tech, the company that produces the Force Suits.