Science and Technology are truly miraculous things -- except when in the hands of a super-genius super-jerk like the Keroro Platoon's recently recovered tactical officer, Sergeant Major Kululu. Already, Kululu is developing biochemical weapons that no Earth medicine can combat, and rays that can turn the entire planet into helpless children! But where can a fugitive alien find test subjects for such diabolical weapons? Where indeed but the Hinata household! Meanwhile, Private Tamama and Angol Moa vie for the Sergeant's affections, Momoka vies for Fuyuki's affections, Natsumi enters a swimsuit competition, and a frog of the fairer sex appears on the scene...

Sgt. Keroro
Sgt. Keroro is the Leader of the Space Invasion Force's Special Advance Team of the 58th Planet of the Gamma Storm Cloud System. He also happens to resemble a frog with too many growth hormones and a touch of wit. During a mission to gather intelligence for the upcoming invasion of Pokopen, his camouflage fails him and he is captured by the Hinata kids. His determination to take over the Earth is second only to his passion for Gundam models.

Private Tamama
An Assault Soldier of the Keroro Team, the (usually) mild-mannered Tamama is the Sergeant's closest ally and biggest fan. He currently resides with Momoko -- and like Momoko, has a rather frightening split personality. He may look cute ... but don't get him angry!

Corporal Giroro
The third member of the Keroro team, this trigger-happy mobile soldier hasn't been seen since Keroro landed on Earth. Does not suffer fools gladly -- especially where fools are defined as 'wimps' or as 'Sergeant Keroro.' Angers easily. Military culture is his life. Intensely attracted to Natsumi's cruelty.

Fuyuki Hinata
12-year-old Fuyuki is a total UFO nut, so when he finds an alien hiding in his bedroom, it's like a dream come true. But his thirst for paranormal knowledge soon transforms into true affection for the incorrigible extra-terrestrial. He's the Sergeant's only real Pokopenian friend.

Natsumi Hinata
Fuyuki's 14-year-old sister is NOT into UFOs -- especially ones that look like frogs and spy on her while she's bathing. Treats the Sergeant as her personal slave. Still hanging onto her reputation as a bully ... very strong, athletic, sarcastic and ruthless. In other words, she lives up to her school nickname of 'The Devil.'

Aki Hinata
The extremely well-endowed mother of Fuyuki and Natsumi is also an extremely dedicated manga editor. When she meets the Sergeant, she is fascinated enough to make him the main character of her new hit manga. Rarely home, due to her enthusiasm for her work -- but when she is, she rules with an iron fist.

Momoko Nishizawa
This 12-year-old billionaire with a split personality has a huge crush on Fuyuki and will do ANYTHING to try and win his affections. Half the time she's incredibly insecure ... the other half, she's FEROCIOUS. She is also Private Tamama's rather dysfunctional 'owner': alternately affectionate and abusive.

Angol Moa
As prophesied by Nostradamus, Angol Moa did indeed come down from the sky to destroy the Earth during the seventh month of 1999. However, the prophet left out that she would be a ditzy, insecure approval addict. Coincidentally enough, she is also a family friend of the Sergeant -- she calls him 'Uncle.'

Mine Yoshizaki
Yoshizaki-san got his start as a doujinshi mangaka (fan artist) who specialized in game-related manga. Aside from Keroro Gunso, he is also the creator of Arcade Gamer Fubuki. Keroro Gunso is serialized in Shonen Ace magazine, Kadokawa's #1 boys manga magazine.