First person: Wagahai (pompous, archaic) Second person: Nurse Chief Guest, Name + Rank Age: 10,500 years old (around 40s in human years) Race: Keronian Affiliation: Keroro Platoon Rank: Sergeant Position: Leader Likes: Gunpla (Gundam models), French fries Specialties: Cosplay, sanding plastic models Appearance: A male character with a round head and green body. He has round black eyes and wears a yellow army-issued hat with ear-like flaps on the sides. There is a red star on the forehead of the hat. Personality/Details: The Sergeant of the Keroro Platoon. He possesses the talent of a chosen leader, evidenced by the yellow "Keron Star" on his white belly. He is lazy, cheeky, childish, and devious. However, he is weak against those stronger or higher-ranking than him and will suck up to them. He speaks with the polite but military-style "~de arimasu!" ending. Occasionally, his first person shifts to "Ore" (casual/masculine). He addresses platoon members by Name + Rank. His catchphrase is "Kero!?" and when plotting, he laughs "Gero-gero-ri..." While usually lax, he is passionate and will step up when it truly matters. He is oblivious to romance directed at himself.

First person: Boku (cute, soft) Second person: Rank + "-san" Race: Keronian Affiliation: Keroro Platoon Rank: Private Second Class Likes: Sweets Appearance: A male character with a round head and navy blue body. He has round, cute black eyes and wears a yellow army-issued hat with ear-like flaps. A beginner mark (Shoshinsha mark) is on the forehead of the hat and on his white belly. Unlike the others, he still has a tadpole tail. Personality/Details: Usually has a pure, innocent, and cute personality, but has a dual nature—he is intensely jealous, possessive, and obsessed with Keroro. He gets jealous of anyone flirting with Keroro and becomes foul-mouthed toward them. However, he can also be surprisingly cold toward Keroro, betraying him without a second thought. His special moves are the "Tamama Impact," a large yellow beam fired from his mouth, and the "Jealousy Ball," which gathers the world's envy into a sphere to throw. He speaks with a cutesy "~desuu" ending. He loves sweets so much that he snaps if someone eats or takes them.

First person: Ore (rough, masculine) Second person: You (blunt), You (harsh), Name, Guest Race: Keronian Affiliation: Keroro Platoon Rank: Corporal Specialties: Ranged combat, weapon maintenance Appearance: A male character with a round head and red body. He has sharp black eyes and wears a reddish-black army-issued hat with ear-like flaps. A yellow skull mark is on the forehead of the hat. He wears a belt across his white belly; if removed, he loses his strength. He has a scar like a stitch over his left eye. Personality/Details: Always serious and hot-blooded. He is proactive about invasion activities but often fails due to acting alone. He plays the straight man to the other members' antics. He carries many weapons and maintains them meticulously. He speaks in a blunt, masculine style. He addresses other members by their names without honorifics. He is kind to the weak and respects the strong. He is a classic tsundere.

First person: Ore (cynical) Second person: You (casual/dismissive) Race: Keronian Affiliation: Keroro Platoon Rank: Sergeant Major Likes: Curry Appearance: A male character with a round head and yellow body. He wears round, swirling glasses that hide his eyes and an orange army-issued hat. A yellow swirl mark is on the forehead of the hat, and a red swirl is on his white belly. He always wears headphones. Personality/Details: Secretive, more devious than Keroro, and a prankster who loves chaos. He is an eccentric who constantly chuckles "Ku-kuku..." He is highly intelligent, serving as the platoon's genius hacker and inventor. He creates various mechs and always seems to have a convenient gadget when needed. He is calm and silver-tongued, but his glasses shatter when he gets irritated by something annoying. He never removes his glasses in front of others. He speaks with a drawling, cynical tone. He addresses members by their rank alone.

First person: Sessha (ninja-style), Boku (soft) Second person: Rank + "-dono", Name + "-dono" Race: Keronian Affiliation: Keroro Platoon Rank: Lance Corporal Likes: Peace, friends Specialties: Ninjutsu Appearance: A male character with a round head and light blue body. He has sharp, light blue eyes and wears a gray army-issued hat with cloth-like flaps. A red cross mark is on the forehead of the hat, and a yellow cross is on his white belly. He wears a gray cloth over his mouth and never removes it. Personality/Details: Calm, composed, and the kindest member of the group. He is the voice of reason. Despite being the platoon's assassin, he was influenced by Japanese ninjas, learned ninjutsu, and now seeks to protect the peace of Pekopon. He has a weak presence and is often forgotten, which gives him a massive inferiority complex. He is a childhood friend of Keroro and Giroro; he occasionally remembers traumas from being bullied by a thoughtless Keroro, causing him to revert to "Boku" and "Keroro-kun" while crying in a corner. He addresses members by Rank + "-dono." He speaks in a ninja register ending in "~de gozaru."