Doruru is a character appearing in the third film of the theatrical Keroro Gunso series. He is a member of the antagonistic group led by Dark Keroro, serving as one of its primary combatants. Doruru has a deep blue skin tone and is extensively equipped with built-in weaponry, earning him the moniker of the arrogant heavy-armed soldier. His equipment includes a light blue hat fitted with rim-mounted laser guns, machine guns attached to both hands, and a back-mounted cannon flight device. He is characterized by a silent and reserved personality, typically communicating using only brief two-character phrases to convey his intentions.

Before the events of the story, Doruru was a trainee soldier belonging to the Keron Army. His service ended in disgrace after he was expelled from his unit for starting a forest fire, following which he vanished and disappeared from official records. He later reemerged as a member of the Dark Keronian小队, a group assembled by the shadowy version of Keroro. As part of this team, his motivations appear rooted in his allegiance to this group and its goals, fighting alongside comrades including Miruru and Shivava.

Within the film's narrative, Doruru functions as a significant opponent, representing a notable threat due to his considerable combat prowess. His fighting ability is said to be on par with that of Garuru, the older brother of the veteran soldier Giroro. This places him as a formidable heavy-weapons specialist whose role is to engage in direct conflict with the protagonists. His personal development and ultimate fate in the story conclude with his defeat, as he is beaten in battle by Giroro within a specific time frame of forty-eight hours. This defeat serves as a key turning point in the film's central conflict between the main characters and their dark counterparts.