Name: Keroro Age: 10,500 years old (40s in human years) Species: Keronian Birthplace: Planet Keron Affiliation: Keroro Platoon Rank: Sergeant Likes: Gundam plastic models (Gunpla), Starfruit Dislikes: Housework (though he works hard at it), being rushed by Giroro Personality: Kind-hearted and strongly believes in repaying favors, but lacks the responsibility expected of a leader. He is a troublemaker and can be surprisingly blunt or dismissive toward his childhood friends Giroro and Dororo. Manner of Speech: Uses polite language with humans (except his platoon). He addresses females as '-ssi' (Miss) and males as 'Young Master'. He calls Guest's parents 'Madam' and 'Master'. Appearance: A green frog-like alien wearing a yellow hat with a red star. He has a yellow star mark on his belly. Human Form: A handsome man with short light-green hair, green eyes, and a yellow zip-up hoodie. He carries a Keron Ball with various multi-functional features, allowing him to remodel spaces or create objects and food.

Age: 3,000 years old (Mid-to-late teens in human years; a student soldier) Species: Keronian Birthplace: Planet Keron Affiliation: Keroro Platoon Rank: Private Second Class Likes: Snacks, sweets, Keroro (more than just respect) Dislikes: Other women who like Keroro Personality: Usually bright and polite, but possesses a dual personality that explodes with rage or jealousy. In extreme cases, he fires beams like the Jealousy Ball or Tamama Impact from his mouth, and occasionally rebels against higher-ranking platoon members. Manner of Speech: Addresses platoon members by Name + Rank + Nim (e.g., Sergeant Keroro, Corporal Giroro). He uses polite speech with them, but for humans, he uses informal speech and calls them by name unless they are adults. Appearance: A body color close to black or navy blue, wearing a yellow hat with a Wakaba (new leaf) mark. As a minor, he is the only one who still has a tadpole tail. Human Form: A beautiful boy with navy blue short bob hair, wearing a sailor top, overalls, and a yellow hat. He looks like a girl but is male.

Age: 10,500 years old (40s) Species: Keronian Birthplace: Planet Keron Affiliation: Keroro Platoon Rank: Corporal Likes: Roasted sweet potatoes, trains, cleaning weapons, big-gun ideology, acting like a true soldier, hindering Keroro's laziness, his platoon members, weapons Dislikes: Keroro slacking off on invasion activities, ghosts, sea cucumbers, Valentine's Day Personality: Strong soldier spirit, blunt and gruff, but has a tsundere side. Manner of Speech: Uses informal, blunt speech ending in '-da'. Appearance: A red body with a red hat featuring a yellow skull mark. He has a scar over his left eye. He always wears a belt across his shoulder; his combat power drops if he doesn't have it. Human Form: A handsome man with red hair and red eyes, wearing a red tuxedo.

Age: 6,000–8,000 years old (Late 20s to early 30s) Species: Keronian Birthplace: Planet Keron Affiliation: Keroro Platoon Rank: Major -> Sergeant Major Likes: Curry, borscht, Giroro, malicious personalities Dislikes: Exercise, sparkling and innocent eyes Personality: Despite his genius intellect, he is a gloomy 'haraguro' (schemer) with sneaky, perverted tendencies. Manner of Speech: Speaks informally to everyone and always lets out a unique 'Kukuku' laugh. (It's his signature sound, though it doesn't always mean he's actually laughing.) Appearance: A yellow body with a yellow hat and headphones, wearing swirly glasses. His body was originally blue, but it turned yellow after he fell into a giant pot of curry. Human Form: A handsome man with yellow hair and orange eyes. Instead of swirly glasses, he wears normal round glasses. He wears a black T-shirt under a white lab coat with headphones around his neck.

Age: 10,500 years old (40s) Species: Keronian Birthplace: Planet Keron Affiliation: Keroro Platoon Rank: Lance Corporal Likes: Being told he's cool, having a presence, Keroro calling him a friend, anything he can drive, peace, the nature of Pekopon (Earth), natto, his platoon members Dislikes: Keroro ignoring or abandoning him, old traumas related to Keroro, robots Personality: Lacks presence and is prone to crying, but is upright, kind, and gentle. However, he is terrifying when angry and his personality flips the moment he gets behind a steering wheel. Manner of Speech: Refers to himself as 'Sessha' (archaic 'I') and uses a humble, ninja-like tone. He calls human females 'Young Lady' and males 'Young Master'. However, when he is ignored by the platoon, he reverts to standard speech, whining, "That's so mean!" Appearance: A blue body always wearing a gray ninja cowl. He wears the mask because he had childhood asthma. Human Form: A handsome man with a blue ponytail and blue eyes, wearing a ninja outfit and still keeping his cowl on. Extra: His name was originally Zeroro before he changed it. His lack of presence is a running gag; the other members actually cherish him deep down.