Dokubon, grandson of Dokurobei (introduced in episode 35 of the 2008 series), is left with the Doronbo Gang to help locate the remaining Dokuro Rings. Physically resembling a younger Dokurobei, he is more cruel and manipulative. He frequently rides the robotic pig Neeton and openly expresses disdain for the Doronbo Gang, often sabotaging their efforts or criticizing them.

He exhibits a bratty demeanor, using pranks and tantrums to assert control and sometimes ending sentences with "beh." Despite cunning tendencies, his capabilities are limited; he relies on Neeton for physical tasks and uses a specialized stick to detect Dokuro Rings and modulate his voice. He shows particular fondness for rice-based meals, especially one topped with a hamburger patty and fried egg.

Dokubon develops an infatuation with Ai-chan, becoming his primary motivation for staying with the Doronbo Gang. His persistent advances are rejected, and Ai-chan attempts to correct his behavior without success. Though generally self-centered, he displays occasional empathy, such as prioritizing a yeti's toothache over retrieving a Dokuro Ring, partly due to reminders of his absent mother.

Later, Dokubon is revealed as the leader of the rival Dokuro Ring Hunters, ensuring the Rings' acquisition. He orchestrates Ai-chan's kidnapping and deploys the Dabinki Mecha to disable Yatter-Mechas. Dokubon and Dokurobei are ultimately disclosed as aliens from Planet XYZ. Dokubon's ambition is to use the Rings—keys to restoring Dokurobei's true form—to wish for Ai-chan's affection and support Dokurobei's plan to harvest human hopes for power.

During the climax, exposure to scrapbook mechas showcasing cherished memories triggers a pivotal emotional shift. A photograph of his mother causes profound homesickness and remorse. He weeps and implores Dokurobei to abandon their attack, leading to their return to Planet XYZ. Dokubon does not reappear when Dokurobei later revisits Earth.