(556) A human-like alien and space detective who is a childhood friend of Keroro. He isn't very good at his job, and instead lives in a cheap apartment on a shoestring budget. Kogoro seems to grin and laugh all the time, regardless of his actual feelings. His hobbies include collecting colored boxes. His appearance and mannerisms are a parody of Kenji Ooba, the star of the tokusatsu series Space Sheriff Gavan.  Source - Wikipedia

Keroro is a frog-like alien sent from his home planet on a mission to conquer Earth. But when his cover is blown, his battalion abandons him and he ends up in the home of the Hinata family. There, he's forced to do household chores and sleep in a dark basement that was once supposedly a prison cell haunted by the ghost of an innocent girl. He even spends his free time assembling Gundam model kits. During his stay, Keroro meets up with subordinates who were also stranded during their failed invasion. 
 
(Source: Anime News Network)

__Hobbies:__ driving, historical research

Israeli actor and dubber. Graduate of the Israeli acting school Beit Zvi. 

Sergeant Keroro and his four subordinates came from the planet Keron to the Earth to conquer. However, without notice, they began to enjoy the life on the Earth. Keroro was supposed to stay with Hitana to get the chance to conquer the Earth, but he became friend with Hinata's son, Fuyuki. 
Today, as usual, Keroro goes to buy his favorite Gundam plastic model with Fuyuki. On their way home, they find a small shrine, and enter. There, they find a vase, and happens to break it. Since the next day, strange things happen all over the town and people are in panic. Inside the vase, Kiruru, Keron's ancient ultimate weapon was sealed. At the moment, Mirara who holds the secret of the Kiruru appears and informs them of the only method to save the Earth. However... 
(Source: AnimeNfo)

Sergeant Keroro is the Captain of the Space Invasion Forces Special Advance Team of the 58th Planet of the Gamma Storm Cloud System, sent to the planet Pokopen (aka Earth) to collect intelligence for his planet's invasion force. He is also a frog. After his ship crash-lands in the planet earth, he takes shelter in the Hinata household, but the two kids, Fuyuki and Natsume, find him and take away his alien weapons. When his people discover that the Pokopenians are aware of him, Keroro is abandoned - left to fend for himself in this hostile world. But he's not alone - four other pre-invasion agents were are also lurking on Earth. 
 
(Source: Tokyopop) 
 
Includes chapter 6.5.