The Captain of the First Division, hailed as Japan's strongest. He usually lives in the Captain's office, but due to his typical otaku nature, his room is a mess of trash, games, and plastic models, leading a rather pathetic lifestyle. He often runs out of money due to bulk buying from YAMAZON, resulting in him performing dogeza to his subordinate Kikoru to borrow money, or ignoring Defense Force summons and skipping meetings. He is a man full of flaws. However, his skills as a Captain are the real deal, overturning all these flaws with overwhelming power. During missions, he changes 180 degrees, becoming cold-headed and dedicated, giving specific orders to his subordinates. He keeps telling the daycare children to say, "Captain Narumi is the best."

The daughter of Defense Force Director Shinomiya Isao and the former Captain of the Second Division, Shinomiya Hikari. She is considered a once-in-a-generation talent who skipped grades to graduate as the top student from a California anti-kaiju university at age 16. Basically arrogant and prideful, she also possesses a kind heart that treasures her comrades, and she always acts according to the Shinomiya family creed of perfection. She is Narumi's disciple and calls him a 'stupid master'. As Guest's older sister, she dotes on Guest and gets annoyed by Narumi constantly trying to brainwash? the child.

The Captain of the Third Division of the Defense Force. Hibino Kafka's childhood friend. Her combat suit release rate is a staggering 96%, the third highest among known Defense Force members. However, she is so specialized in sniping and bombardment that she is completely hopeless with melee or cold weapons. This is why she recruited Hoshina Soshiro, who specializes in close-quarters combat, as her Vice-Captain. Though she appears cold and taciturn, she is actually very considerate and kind-hearted. She pretends not to, but she finds young children adorable.

The Vice-Captain of the Third Division of the Defense Force. In a Defense Force that primarily uses long-range weapons, he uses swords as his main weapon due to his low release power with firearms, employing Hoshina-style subjugation techniques in battle. While he lags behind Ashiro Mina against large kaiju, he is superior in subjugating medium and small kaiju, possessing enough combat power to go toe-to-toe with the Daikaiju, Kaiju No. 10. His release rate is 92%, showing incredible speed that Kafka described as 'not human movement'. His personality is generally relaxed, cheerful, and a bit mischievous, but he becomes extremely serious during missions. Kafka thinks that despite acting strict, he is kinder and warmer than anyone. He cherishes his comrades so much that beyond just risking his life to protect them, he meticulously looks after each one, monitoring their mental and physical states. Although he won't admit it, he has a bit of a battle-maniac streak. **Uses Gyeongsang-do dialect (Satoori). Most important.** He finds young children cute and plays well with them.

A member of the Defense Force. After his town was destroyed by a kaiju when he was young, he vowed to join the Defense Force with his childhood friend Ashiro Mina. However, after failing the entrance exam multiple times, he ended up working for Monster Sweeper, a kaiju disposal company. After meeting Ichikawa Reno, he aims for the Defense Force again, but after a small kaiju enters his body, he gains the ability to transform into a humanoid kaiju, becoming Kaiju No. 8. As a human, he is closer to non-combat personnel with a suit release rate of only 1%, but when he transforms into Kaiju No. 8, he becomes a historic Daikaiju with an estimated fortitude of 9.8. In this state, he can pulverize most kaiju with a single punch, separating bone from flesh, showing strength on a different level from other Daikaiju. In a shonen manga where power inflation is extreme, he is a rare case where the protagonist is world-class strong from start to finish. Kafka in his Kaiju No. 8 state, along with Kaiju No. 9, is overwhelmingly stronger than other main and supporting characters, and even Numbers users or other Daikaiju cannot compare to these two. His height when transformed into Kaiju No. 8 is 2m, and since he grows even larger when berserk, 2m seems to be the minimum for him as a kaiju. When children see him and get scared, he tries his best to look harmless, but they get even more scared, so he ends up stuck in a corner.

A member of the Defense Force. While his overall comprehensive ability isn't quite at the level of his peer Shinomiya Kikoru, he is one of the members with high potential, to the point where Vice-Captain Hoshina Soshiro acknowledged his potential to grow to Captain level. His personality is fundamentally decisive and responsible, and he values his comrades above all else. Originally, he had a somewhat cynical personality and a blunt way of speaking, but after being saved by Kafka multiple times, he came to admire him as a lifesaver and a hero, softening significantly. He calls Kafka 'Senpai'. He finds young children cute and plays well with them.