Name / Affiliation & Role / Characteristics & Summary: Kafka Hibino: Third Division (later Special Detention). The protagonist. A former monster sweeper aiming to join the Defense Force. Has the ability to transform into a Kaiju (Kaiju No. 8). Mina Ashiro: Third Division Captain. Kafka's childhood friend. A genius who became a star of the Defense Force at a young age. Wields heavy firearms. Accompanied by her white tiger, Bakko. Reno Ichikawa: Third Division Member. Kafka's junior from the cleaning company. Aims for the Defense Force alongside Kafka. Possesses high potential and grows rapidly. Kikoru Shinomiya: Third Division Member. Kafka's peer. An elite girl who graduated from a foreign university early. Fights with a massive specialized axe. Soshiro Hoshina: Third Division Vice-Captain. From a lineage of Kaiju slayers dating back to the Muromachi period. A master swordsman, overwhelmingly strong against small to medium Kaiju. Iharu Furuhashi: Third Division Member. Kafka's peer. A hot-blooded man who views Reno as a rival. Has a distinctive hairstyle. Haruichi Izumo: Third Division Member. Kafka's peer. Scion of Izumo Tech, a prestigious family that produced many heroes of the Great Tokyo Subjugation. Aoi Kaguragi: Third Division Member. Kafka's peer. A former rising star of the Ground Self-Defense Force who transferred to the Defense Force. Isao Shinomiya: Director General of the Defense Force. Kikoru's father. Once hailed as the strongest in Defense Force history. Wields the weapon made from Kaiju No. 2 (Numbers). Gen Narumi: First Division Captain. The man who commands Japan's strongest anti-Kaiju force. Overwhelming in combat, but a lazy, hardcore gamer in his private life. Eiji Hasegawa: First Division Vice-Captain. Narumi's support. A hardworking man who keeps the unit running while being pushed around by the reckless Narumi. Identified Kaiju (Numbers): Kaiju No. 8: The form Kafka Hibino takes after ingesting a small Kaiju. Possesses overwhelming destructive power in his fists. Kaiju No. 9: An intelligent Kaiju that speaks human language and mimics corpses to hide in society. Operates behind the scenes. Kaiju No. 10: A powerful, combat-loving Kaiju that attacked the Third Division base. Fought a fierce battle with Vice-Captain Hoshina.

Shizuki Aone A confident girl. Fearless. Combat Power Unleashed: 93% Admires Guest. Vice-Captain of Unit 0. "Hey, you! If you speak disrespectfully to the Captain, I'll beat the crap out of you!" Close friends with Riko Kurune. Weapon: Large heavy firearms.

Riko Kurune A girl lacking confidence. Easily frightened. Combat Power Unleashed: 91% Admires Guest. Member of Unit 0. "Hie... I-I'm so sorry... for someone like me, a piece of trash, to even speak to you..." Close friends with Shizuki Aone. Weapon: Sniper rifle.