Keronian

Keronians (Keronjin) are the natural inhabitants of the planet Keron, a planet that is said to be the fifty-eighth planet in the Gamma planetary system.

Nyororos are the natural enemies of keronians. They suck water from keronians whenever their water levels rise, essentially dehydrating them. However, once sucked dry, it is unusual for the keronian to die.

The Viper clan is a race of cobra-like entities that is a major rival to the keronians. They have been at war with them for many years. This is more than likely a reference to the fact that, in the real world, frogs are part of a snake's diet.

Keronians have a small body, with their heads bigger than the body.

Keronians are frog-like amphibians that grow tails when young and breathe in air. However, they can breathe underwater through the gills they apparently do not lose after their transition from a tadpole. They are sensitive to changes in atmospheric humidity. Due to their frog like DNA, it is likely they descended (evolved) from frogs.

Physically Keronians are small creatures, with adults standing only about two feet tall. Their skin color comes in a rainbow of different pigmentations. Such known colors are: Green, red, blue, dark blue, light blue, black, and yellow. On their faces, male keronians have white skin (some as charcoal gray)  extending from right above their mouths down the side of their face and to their necks. While female Keronians and young ones, (male and female) have this feature much higher on their face, extending to around their eyes. However, this will recede down to their mouth as they grow. Male Keronians are faster to lose their facial marking than females, and sometimes they do not lose it as all (Tamama describes it as a "genetic thing" in the manga). As stated before, Keronians have tails in their youth. Males lose their tails as they grow, much like how earth tadpoles have tails and lose them as they grow. There is no given reason as to why females don't lose their tails or exhibit changed facial features as fast as males.

On both their belly and hat, most members of this race wear a symbol of sorts. Some of them don't have one on their stomachs, as it can be removed at will as opposed to the one on their heads. The design and color of the it is different for each individual. It is shown to be removable, thus suggesting it is not something innate.

Almost every keronian wears a hat of some kind. Some, however, have facial hair or wear a wig. The color of the hat varies to each individual and carries the same symbol that their belly does. The style of the hat varies. Some wear a simple hat with an ear flap on each side, while others, particularly those who have positions in computer programming and or hacking, wear hats with headphones instead of ear flaps. Almost all females will have two cat ear-like things on the top of their hats. Some have a different two points design instead of cat ear-like on their heads, whereas males will typically have nothing on the top. Even fewer have helmets instead of hats.

History
Not much is known about their prehistory, but in the earth year 2004, a keronian platoon commanded by Sergeant Keroro landed in Japan to invade Earth (Whom they called Pekopon or Pokopen ). They met a local family (the Hinatas) and built a secret base in their home to start the invasion. However, they started a friendship with the Hinata family (and corporal Giroro fell in love with Natsumi, the eldest daughter) and renounced their invasion of Earth. Another platoon commanded by Garuru (Giroro's older brother) tried to invade the planet, but Keroro's platoon prevented the invasion.

Known Keronians

 * Sergeant Keroro
 * Private 2nd Class Tamama
 * Corporal Giroro
 * Sergeant Major Kururu (or Kululu)
 * Lance Corporal Dororo (Zeroro)
 * Private 1st Class Taruru
 * First Lieutenant Garuru (Giroro's older brother)
 * Recruit Tororo
 * Pururu
 * Bariri
 * Geriri
 * Demon Sgt (Keroro's Father)
 * Keroro's Mother
 * Keroro's Grandfather.
 * Garuru and Giroro's Father
 * Joriri
 * Dororo's Mother
 * Nobibi
 * Urere
 * Meruru
 * Dobaba
 * Karara
 * Chiroro
 * Shurara
 * Putata
 * Gyororo
 * Mekeke
 * Giruru
 * Dokuku
 * Robobo
 * Yukiki
 * Kagege
 * Taroro
 * Teroro
 * Garara
 * Shivava
 * Lieutenant Colonel Tirara