Sergeant Keroro (Keronian)

Keroro (ケロロ, Keroro?) is a fictional manga and anime character and the main protagonist of Mine Yoshizaki's Sgt. Frog series. In the anime, he is voiced by Kumiko Watanabe. In the English dub he is voiced by Todd Haberkorn. In Cantonese he is voiced by Joyce Luk.

Keroro is a sergeant of Planet Keron's Army, and the commander of the Keroro Platoon.

According to Earth's Gregorian calendar, Keroro's birthday is December 9. His blood type is O. Watanabe, Keroro's seiyū, has stated that she played Keroro as someone who was about 45 years old. Keroro described himself to be a child when Nintendo started selling the Game & Watch systems. Since Keroro knew Angol Mois since she was supposedly "little", Keroro is at least more than 500 years old.

Keroro's name comes from the Japanese onomatopoeia for the sound a frog makes ("kerokero").

Keroro's body is green, accompanied with a yellow headgear with a red star in the middle (a yellow star is also seen on Keroro's stomach). According to Lieutenant Garuru, the star is the symbol of the Keron Force as well as its commanding officers. The star itself has the ability to lend it's dignity to the wearer. However, since Keroro lacks character, the effect is nullified while he wears it. When Keroro is met with an explosion, he suddenly grows a large black afro as a running gag reference to "Afro Gunsou", the anime's first ending theme song.

Source: Wikipedia