Black Star is a character and a main antagonist of the manga. Just like Shin Keroro, he is made by Kiruru's DNA.
He first appeared in volume 23 of the manga, then again as a mini figure in Keroro Land 40. But his history is unknown. Though it's suspected that he is the first attempt of making Shin Keroro that failed.
He is an evil version of Shin Keroro. He very resembling to Shin Keroro except he's mostly black and does not wear a cap except he has long, wavy ear-like appendages, and wears blue rings all over his body, (appendages, wrists, and neck as a collar) just like Shin Keroro wearing a round red ring as his collar and a bracelet. His eyes are shaped semi circles similar to Giroro's eyes and his irises are red-colored, making it more evil-looking. His symbol is an upside down star, opposite to Shin Keroro's Keron Star that its black on his stomach and its white on his forehead.
- Unlike his official artwork, his irises are yellow as a mini figure.
- In the manga he only appeared for a chapter as a antagonist.
- His first appearance with volume 23 of the manga.
- A figure in the cover of the Keroro Land Volume 40, after Shin Keroro as a mini figure in the cover of Keroro Land Volume 39.
- Before his official colors are revealed, his rings all over his body are red-colored instead of blue, by fans.