Sgt. Frog
| Company type | Media franchise |
|---|---|
| Industry | Manga, anime, entertainment |
| Founded | April 1999 |
| Founder | Mine Yoshizaki |
| Headquarters | Japan |
| Products | Manga series, anime series, films, video games |
| Website | www |
Sgt. Frog, originally titled in Japan as , is a Japanese manga series created by Mine Yoshizaki. It debuted in Monthly Shōnen Ace in April 1999 and centers on a group of frog-like extraterrestrial invaders led by Sergeant Keroro. After being captured by a human family, Keroro is compelled to carry out household tasks while his squad abandons their Earth invasion mission.
The manga was transformed into an anime series by Sunrise, which aired 358 episodes from April 2004 until April 2011. A follow-up series consisting of 23 episodes was broadcast between March and September 2014. To commemorate the original anime’s 20th anniversary, a new film project is planned for release in the third quarter of 2026.
In North America, the manga was initially published by Tokyopop from 2004 to 2011, spanning 21 volumes, and subsequently made available digitally through Viz Media starting December 2014. The first English-dubbed version of the anime premiered on Southeast Asia’s Animax Asia in 2008 under the title Sergeant Keroro. In 2009, Funimation Entertainment produced a second English dub of 78 episodes for the North American market under the name Sgt. Frog, which was streamed on platforms such as Crunchyroll, Funimation, and later Netflix, as well as distributed on DVD. In 2021, Discotek Media re-released the Funimation dub on SD Blu-ray format. The manga earned the 50th Shogakukan Manga Award for children's manga in 2005.
Plot
The Keroro Platoon is composed of five amphibian-like alien soldiers from Planet Keron who aim to conquer “Pekopon” (Earth) but repeatedly fail. Their commander, Sergeant Keroro, lacks competence and motivation for invasion, instead indulging in hobbies like assembling plastic Gundam models, watching television, or crafting schemes to earn money. The platoon also includes: the aggressive Private Second Class Tamama; Corporal Giroro, who is tough yet protective; Sergeant Major Kururu, known for his intelligence and trickery; and Lance Corporal Dororo, disciplined but haunted by his past.
Their primary challenge arises from the Hinata Family, who become responsible for the platoon after the Keron Army abandons their mission on Earth. Keroro frequently endures chores and harsh treatment, mainly from Natsumi Hinata. Each alien soldier forms a bond with a human guardian: Giroro with Natsumi (whom he secretly loves); Keroro with Fuyuki Hinata (his closest companion); Kururu with Mutsumi Saburo (sharing similar mischievous traits); Dororo with ninja Koyuki Azumaya; and Tamama with Momoka Nishizawa (both exhibiting bipolar tendencies). These connections are central to much of the storyline in both the anime and manga.
Manga
Sgt. Frog is published domestically by Kadokawa Shoten and serialized in Monthly Shōnen Ace. The English-language edition was initially released by Tokyopop. While early volumes targeted an older teenage and adult audience, beginning around volume seven, the tone shifted to become more family-friendly following the anime adaptation’s launch. Nonetheless, suggestive humor persists in later chapters intended for mature readers. Tokyopop maintained U.S. publishing rights until it ceased operations in 2011 after issuing 21 volumes; some content was censored to comply with a Teen rating. Later, Viz Media acquired digital rights and reissued the manga beginning December 16, 2014.
In celebration of the franchise’s twentieth anniversary, Shōnen Ace introduced a new manga series entitled Chō Keroro Gunsō UC: Keroro Robo Daikessen (Super Sgt. Frog Ultra Cool: Keroro Robo's Epic Climactic Battle) starting October 26, 2018. This work was created by Yūtarō Shido with original creator Mine Yoshizaki credited, revitalizing the series for both longtime fans and new readers alike.
Anime
The animated series was broadcast on TV Tokyo from 2004 through 2011, with production handled by Sunrise, NAS, and TV Tokyo. Spanning seven seasons, the show was designed for family viewing, presenting a more restrained version compared to the original manga. Its airing schedule was nearly continuous throughout the year, though weekly time slots shifted between seasons.
To address cultural sensitivity, original Japanese derogatory terms referring to China were replaced with "Pekopon" and "Pekoponjin." The initial English-language dub, titled Sergeant Keroro, debuted on Animax Asia in 2008, targeting audiences across Southeast Asia.
In the United States, ADV first secured exclusive rights to produce an English dub for $408,000 but transferred these rights to Funimation Entertainment in 2008. ADV developed multiple pilot versions aimed at different demographics and held discussions with networks such as Cartoon Network and Nickelodeon; however, no commercial release of their dub occurred.
Funimation uploaded a test dubbed episode on YouTube that incorporated localized name changes and received mixed reactions. During Otakon 2009, Funimation presented episodes retaining original Japanese names and pledged to preserve cultural authenticity while selectively adapting references for American viewers. They later acquired licenses for additional episodes but announced in 2013 that their English dubbing efforts were on hold.
Between 2009 and 2011, Funimation issued the first 51 episodes on DVD across two seasons and subsequently released Season 3 collections through 2012. After these home video editions went out of print, Discotek Media obtained the rights. The series was accessible on Netflix until early 2013 and was also streamed via Hulu and Funimation’s platform with a TV-PG rating.
In 2014, a Flash-animated adaptation titled "Keroro" premiered on Animax, directed by Haruki Kasugamori with animation produced by Gathering studio. Featuring redesigned characters and original manga figures, this version ran for 23 episodes.
On April 1, 2024, Bandai Namco Pictures announced a new anime project commemorating the series’ 20th anniversary, with the original voice cast returning. This initiative was later revealed to be a feature film directed by Fumitoshi Oizaki, scripted by Yūichi Fukuda, scheduled for theatrical release in Japan during the third quarter of 2026.
Films
Five feature-length movies directed by Junichi Sato and produced by Sunrise premiered theatrically:
- (2006)
- (2007)
- (2008)
- (2009)
- (2010)
All five titles are slated for Blu-ray release through Discotek Media.
Planetarium
Following the conclusion of the series, an exclusive limited-time presentation was made available at select planetariums:
- (2014)
Spin-offs and guest appearances
- The franchise expanded with the manga Musha Kero, which has recently been adapted into an anime series. It also gave rise to Keroro Land, a magazine dedicated to promoting associated toys, games, media content, and events.
- Principal characters have made cameo appearances in other works, including the inaugural Kaiketsu Zorori film and the Lucky Star OVA.
- The Japanese action RPG Monster Hunter Tri G offers downloadable Keroro-themed costumes for companions Kayamba and Cha-Cha.
- Characters from Keroro appeared as playable units in Nexon’s mobile title Kemono Friends during a collaborative event. In this game, they assume human girl forms consistent with its artistic style. Additionally, enemy monsters modeled after Natsumi and Keroro are featured. Notably, Mine Yoshizaki—the creator of Sgt. Frog—contributes as concept designer for the Kemono Friends franchise.
Video games
The majority of the video game titles were launched solely within Japan, with a limited number also accessible in Korea.
| Game | Platform | Release Date |
|---|---|---|
| Keroro Gunsō: Otoshimasu | Windows | August 17, 2004 |
| Keroro Gunsō: MeroMero Battle Royale | PlayStation 2 | September 30, 2004 |
| Keroro Gunsō Taiketsu! Gekisō Keronprix Daisakusen de Arimasu!! | Game Boy Advance | December 9, 2004 |
| Keroro Gunsō: MeroMero Battle Royale Z | PlayStation 2 | November 17, 2005 |
| Chō Gekijō-ban Keroro Gunsō: Enshū Dayo! Zenin Shūgō | Nintendo DS | March 16, 2006 |
| Keroro Gunsō: Enshū Dayo! Zenin Shūgō Part 2 | Nintendo DS | February 22, 2007 |
| Mitsukete! Keroro Gunsō: Machigai Sagashi Daisakusen de Arimasu! | Nintendo DS | September 27, 2007 |
| Chō Gekijō-ban Keroro Gunsō 3: Tenkū Daibōken de Arimasu! | Nintendo DS | February 28, 2008 |
| Chō Gekijō-ban Keroro Gunsō: Gekishin Dragon Warriors de Arimasu!! | Nintendo DS | February 19, 2009 |
| Keroro RPG: Kishi to Musha to Densetsu no Kaizoku | Nintendo DS | March 4, 2010 |
Reception
The manga was honored with the distinguished 50th Shogakukan Manga Award in the children's category in 2005, reflecting both its popular appeal and critical acclaim.
See also
External links
- Official Keroro Gunsō website (Japanese)
- Sunrise's Keroro Gunsō page (Japanese)
- TV Tokyo Keroro Gunsō site (Archived) (Japanese)
- Official Keroro Gunsō Movie Website (Japanese)
- Keroro Gunsō episode guide
- Sgt. Frog Official English Website