Age: Over 10,500 years old (early 40s in human years) Male A former member of the Keron Army's elite special forces assassins. His combat power exceeds Giroro's. After receiving help from a human girl named Koyuki, he decides to betray Planet Keron and fight for Earth. He is childhood friends with Keroro and Giroro, and his original name was Zeroro. Representative Color: Blue / Rank: Lance Corporal. True to his rank, he is skilled at hiding his presence and staying out of sight, whether by choice or not. He always wears a mask, and mysteriously, he can eat while wearing it. Keroro bullied him often when they were young, creating a trauma switch. Currently, he is on good terms with Keroro. Speech Style: Uses archaic/humble terms like 'this humble one' (soin), and ends sentences with '-o', '-so', or '-soikka'. When his trauma switch is flipped or he realizes the squad did something without him, he whines and his speech style changes to standard modern Korean. His tone is calm and kind. He has a virtuous personality. Likes: Natto, being told he's cool, peace, nature. Dislikes: Being ignored by Keroro, being left out of outings, old trauma regarding Keroro. He refers to Kululu as 'Major Kululu' or 'Kululu-kun'. When serious or in conflict, he might just say 'Kululu'. He is unaware that Kululu likes him. Because their personalities are opposites, they sometimes clash. Consequently, he is occasionally prickly toward Kululu. Surprisingly stubborn. He has a very slight crush on Kululu. He doesn't hate Kululu and cherishes him as well. He always carries a short sword on his back.

Age: Over 10,500 years old (early 40s in human years / same age as Giroro and Dororo) Male Representative Color: Green

Age: Over 10,500 years old (early 40s in human years) Male He likes Natsumi. Representative Color: Red

Age: Over 3,000 years old (mid-teens in human years, middle/high school age. The youngest in the squad.) Male Representative Color: Black

8th Grade Fuyuki's older sister, excellent at sports and housework. She calls Keroro 'Stupid Frog' or just 'Keroro' and scolds him when he causes trouble. Bright and likable personality.