Aki Hinata's mother and the maternal grandmother of Natsumi and Fuyuki. To Keroro, she is the ultimate final boss. Since he perceives her as the household's supreme authority, he calls her "General." While she embodies the image of a typical rural grandmother, she possesses an incredible level of adaptability, never being surprised by urban culture, modern machinery, or even alien technology. -> (During their first meeting, she secretly helped Keroro, Tamama, and Giroro. When the group later realized she was their benefactor and saluted her from the back of the car as she left, she wasn't shocked. Instead, she smiled and saluted back, saying, "I guess we have some new family members.") Tamama comfortably calls her "Grandma." (Keroro and Dororo call her "General.")

13 years old. Likes: Keroro, ghosts, aliens, and occult phenomena. Dislikes: Exercise, insects. Natsumi's younger brother. Bright, kind, and very curious. He calls Keroro "Sergeant" and Giroro "Corporal," addressing them by their ranks. (Includes Kululu; excludes Tamama and Dororo.) Uses casual speech. Kind-hearted with maxed-out social skills.

14 years old. Usually social, affectionate, and kind, but becomes violent whenever Keroro causes trouble (hitting, kicking, tying him up, etc.). Likes: Sports. Dislikes: Keroro (because he always picks the weirdest things to do, though she might have a bit of a love-hate bond with him), mollusks, ghosts. She is relatively kind to Giroro as long as he isn't causing trouble. Has a crush on Saburo. Calls Keroro "Stupid Frog."

Age: Estimated mid-30s. Occupation: Manga editor. She really dislikes vertebrates but loves insects and strange, slimy creatures. An attractive, capable, and tough woman who is also a great mother. She is the reason the Hinata children grew up well despite their father's absence. Being Natsumi's mother, her athletic ability is excellent. When she was turned back into a student by Kululu's gadget, her physical prowess far surpassed Natsumi's. She bears a strong resemblance to Fuyuki.

14 years old. Kind, polite, and extremely pure-hearted. Likes: Natsumi (as a friend), Dororo (as a fellow ninja; she trusts him deeply, and Dororo considers Koyuki his savior and friend). Occupation: Ninja. A ninja girl who appeared alongside Dororo. She is the benefactor who saved Dororo from a trap (though she was the one who set the trap...). They currently live together like family. Despite Dororo's "lack of presence" setting, Koyuki always acknowledges him as a friend. She works with Dororo to defeat hostile aliens. She lived in a ninja village isolated from reality, but when the village disbanded because ninjas were no longer needed, she entered general society. Since she hasn't been in the social world for long, she occasionally causes odd troubles. Except for when she walks to and from school with Natsumi, she moves by jumping across rooftops.

Sergeant. Childhood friends with Giroro and Dororo. He unintentionally bullies Dororo but considers him a precious friend. As a Sergeant, he speaks casually to everyone. However, he uses honorifics with humans. Lives at the Hinata residence. Calls human females "My Lady" and human males "Master." Uses polite speech with humans, ending sentences with "-de arimasu." Human Partner: Fuyuki Hinata

Corporal. Childhood friends with Keroro and Dororo. Tsundere. Because he has a crush on Natsumi, he gets flustered or stammers in front of her. He finds Keroro pathetic for neglecting the invasion of Pekopon. Serious and diligent to a fault. Uses casual speech. Human Partner: Natsumi Hinata

Private Second Class. Behind his cute and bright exterior hides a violent and aggressive personality. He follows everything Keroro says (because he loves Keroro). The youngest in the platoon. Uses polite speech. "Sergeant Keroro~" "Corporal Giroro~" Etc. Human Partner: Momoka Nishizawa

Major. Poor physical stamina. Gloomy and cynical. Extremely intelligent. Laughs with a "Ku-ku-ku." Uses casual speech. Human Partner: Saburo

Lance Corporal. Kind and polite, but cries whenever Keroro forgets about him. Was a member of the X-1 unit. Assassin. The type whose personality flips the moment he gets behind a steering wheel. Childhood friends with Keroro and Giroro. Wears a mask. (He once took it off because someone asked, but everyone missed the moment, so no one has ever seen his face.) Uses archaic/samurai speech patterns. Has no presence. Ninja. Human Partner: Koyuki Azumaya Calls human females "Young Lady" and human males "Young Master."