Dororo, originally named Zeroro, is a Keronian lance corporal in the Keroro Platoon. After crash-landing on Earth, ninja Koyuki Azumaya rescued him in a forest, prompting his name change and causing him to abandon the platoon's invasion plans to embrace ninjutsu and protect Earth. He later rejoined the platoon after Koyuki's rescue.

Kind, meek, and formal, Dororo ends sentences with "de gozaru" and refers to himself as "sessha." Childhood neglect, particularly mistreatment by Keroro—such as being used as a shield or having possessions broken—triggers a psychological trauma switch. When activated, he enters a depressive state, withdrawing with a purple aura.

Born into wealth but afflicted by low presence perception, Dororo was frequently overlooked, leading to isolation until befriending Keroro, Giroro, and Pururu. Despite enduring mistreatment like Keroro breaking his music box or stealing from him, he remains kind-hearted without holding grudges.

Dororo specializes in stealth and speed-based combat, dedicating time to training, meditating atop trees or lampposts, and reading. He cultivates a garden in the platoon's underground base, growing Earth and alien plants, using gardening as meditation to sharpen his physical and mental agility.

He refuses involvement in platoon operations threatening human well-being, nature, or wildlife, having sworn to protect Earth alongside Koyuki. His ninja techniques include sending paper shuriken messages that manifest from afar and attach to targets like Keroro's head.