Donabenabe, also known as Donabezawa Nabeo, is a supporting character who first appears in the ninth episode of Nerima Daikon Brothers. He arrives at the field belonging to the main characters under the cover of night, immediately establishing himself as a figure of mystery and ulterior motive. His public identity is the boss of a newspaper agency called Nerimagari, which is said to have a bad reputation. In this capacity, he approaches Hideki, one of the brothers, and attempts to persuade him to sell the Nerima field, the sacred land where the protagonists grow their daikon radishes and dream of building a concert dome.

Donabenabe’s primary motivation is tied to a larger scheme orchestrated by Prime Minister Oizumi, a parody of a real-world political figure. It is eventually revealed that Donabenabe is not simply a land developer or a shady businessman but is in fact one of the "children" of Prime Minister Oizumi. This term refers to a group of loyal subordinates or elected officials who carry out his will. In this role, Donabenabe serves as an agent working toward the privatization of Nerima and the acquisition of the main characters' field for the Prime Minister’s ambiguous projects. He is a deceptive and manipulative figure who uses his newspaper agency as a front to get close to the protagonists and exploit their dreams.

Despite his antagonistic function, Donabenabe forms a complex relationship with the main trio, particularly with Hideki. For a time, he and his associate Yûkeru Hakushon manage to sway Hideki and Mako to their side, creating a rift among the Daikon Brothers. The brothers seem to develop a genuine, if misguided, attachment to Donabenabe and Yûkeru, even holding small funeral ceremonies for them after they are seemingly eliminated by Prime Minister Oizumi. This indicates that while Donabenabe is deceptive, he is capable of projecting a charismatic or pitiable persona that elicits sympathy.

His most notable ability is his power of persuasion and his access to considerable resources. He is shown commanding a baseball team that he deploys as muscle during conflicts. He also wears a distinctive badge, which features a lion and also functions as a communicator or transmitter. This badge is a key piece of evidence linking him to his true master, as it matches Yûkeru’s badge and ultimately leads to the revelation of their allegiance to Prime Minister Oizumi. His role in the story culminates in the final episodes, where he and Yûkeru are hit by a special laser weapon. Rather than being destroyed, they are transformed into mind-controlled "lions" clad in lion costumes, serving as unwilling foot soldiers for Oizumi against the protagonists. In this state, they attack their former allies until the power of a supernatural microphone, used to sing the series’ opening theme, creates shockwaves that restore them to their normal selves. Through this development, Donabenabe transitions from a calculating antagonist and false friend to a puppet of a greater evil, before finally being liberated. His ultimate fate after being freed is to be reunited with the other characters in the restored peace of Nerima.