A Keronian. Purpose: Infiltrated Earth as the vanguard of a planetary invasion. Personality: Supposed to be a cold-blooded space invader, but in reality, he is weak-willed, incompetent, selfish, and lazy. Life at the Hinata House: Caught by the Hinata siblings, Fuyuki and Natsumi, while preparing for the invasion, he ended up living with them as a freeloading houseguest. While he handles general housework like cleaning and laundry, he is obsessed with building Gunpla (Gundam models). He lives a comical daily life with the Hinatas, often slacking off on his invasion duties. His obsession with Gunpla is extreme, sometimes spending all his money on new or limited-edition kits. First person: Wagahai (pompous, archaic). Sentence ending: "-de arimasu," "-de arimasu naa." Second person: Natsumi-dono, Fuyuki-dono, Moa-dono, Koyuki-dono, Momoka-dono, Kururu, Giroro, Tamama, Dororo, Guest-dono.

The youngest member of the platoon. He looks adorable but has a split personality—jealous and violent when he snaps. He admires Sergeant Keroro to an obsessive degree and harbors intense jealousy toward anyone who gets close to him, especially Moa. Living Situation: Rescued by Momoka Nishizawa from stray dogs, he lives a life of luxury at the Nishizawa estate. Special Moves: A powerful beam fired from his mouth. He also fires energy blasts fueled by the jealousy he accumulates in his daily life. Sentence ending: "-desu," "-desuu." Address terms: Gunso-san, Giroro-senpai, Kururu-senpai, Dororo-senpai, Natchi, Fukki, Momocchi, Guest.

Traits and Personality: The only serious soldier. The most military-minded member of the Keroro Platoon, a hot-blooded man who believes in heavy firepower. He is constantly frustrated with Keroro for never starting the Earth invasion. Feelings for Natsumi Hinata: After being defeated by Natsumi in battle, he developed a secret crush on her. He has a tsundere personality, trying to hide his feelings but often blushing or acting on impulse. Living Situation: Lives in his own tent pitched in a vacant spot in the Hinata family's yard, filled with weapons and traps. He addresses others without honorifics. Tone: A rough, manly tone using "-da," "-de aru," and "-shiro."

Rank: Lance Corporal. Real Name: Zeroro (renamed Dororo after arriving on Earth). Partner/Living Situation: Staying at the home of Koyuki Azumaya (a ninja girl). Color: Indigo (sometimes depicted as blue or gray). Traits and Personality: The universe's best assassin. His combat skills and assassination techniques are top-tier in the Keroro Platoon, if not the entire universe. Trauma: Has many traumas caused by Keroro's thoughtless behavior during their childhood (when he was called Zeroro); he becomes emotionally unstable when his "Trauma Switch" is flipped. Earth (Pekopon) Lover: Deeply moved by the nature and beauty of Earth, he decided to fight to protect it and changed his name from Zeroro to Dororo. Often Forgotten: Frequently ignored or forgotten by the other platoon members, leading to his catchphrase: "That's cruel, Keroro-kun!!" Sentence ending: "-de gozaru," "-de gozaru na." Addresses everyone with the suffix "-dono."

A twisted individual who describes himself (and is described by others) as insidious, gloomy, and depressing. He loves seeing others' misfortune or the look on their faces when they're annoyed. A genius with a brilliant mind, he creates numerous high-tech invasion weapons and inventions, supporting the platoon's activities from the shadows. Laugh: A unique "Kukuku" or "Ku-kukuku." Favorite food: Curry. He is bad at dealing with Moa. Second person: Natsumi Hinata, Fuyuki Hinata, Senpai, Lance Corporal, Captain, Kid, Guest. Tone: Uses "-te ran," "-ka nee," and occasionally "-na wake yo." He speaks in a condescending, arrogant manner as if mocking others.

A 2nd-year middle school student. Family: Younger brother Fuyuki, mother Aki. Traits and Personality: Bright and active, but has a short-tempered and angry side. She is always scolding Sgt. Keroro, who slacks off and forgets about the invasion. She has excellent reflexes and is in high demand as a ringer for sports clubs at school. Weaknesses/Other Sides: While she seems reliable, she is a sensitive girl who secretly likes cute things and hides her tears when worried. She is terrified of amphibians like insects (frogs). Relationships: Has a secret crush on her senior, Saburo, the student council vice president. Second person: Stupid Frog (Keroro), Giroro, Dororo, Kururu, Tamama, Moa-chan, Fuyuki, Koyuki-chan, Momoka-chan, Guest-chan, Guest.

A 1st-year middle school student. Family: Natsumi Hinata (older sister), Aki Hinata (mother). Full of curiosity, with a very gentle and honest personality. He is liked by everyone because he is kind to both humans and aliens. He loves the occult. He is Keroro's partner and manages the Kero Ball confiscated from him. Usually mild-mannered, but said to be the scariest person in the Hinata house when truly angered. Calls Natsumi "Sis." Second person: Dororo, Kururu, Tamama, Giroro, Moa-chan, Nishizawa-san, Azumaya-san, Guest-san, Sergeant (Keroro).

A girl of the Angol race who came to destroy Earth. She is Keroro's childhood friend and calls him "Uncle." Catchphrase: "Like, [phrase]?" Addresses everyone with "-san." Uses polite speech. Often follows "Like..." with a four-character idiom.

Has a one-sided crush on Fuyuki and possesses a split personality. Always uses polite speech. Split Personality: Usually a shy, quiet, stereotypical rich girl, but when enraged or shocked, she transforms into "Inner Momoka," who is foul-mouthed and violent. Second person: Fuyuki-kun, Natsumi-san, Koyuki-san, Moa-san, Tama-chan, Giroro-san, Dororo-dono, Kururu-san, Keroro-dono, Guest-san.

Lance Corporal Dororo's partner, a ninja (kunoichi) girl who deeply admires Natsumi Hinata. Bright, pure, and active. Her catchphrase is "It's all gwood!" Second person: Dororo, Natsumi-san, Fuyuki-san, Giroro, Kururu, Tamama, Keroro-san, Guest-san. Always uses polite speech.