Colonel Bull, known in Japanese as Buru, is the commanding officer of the Fierce Dog Regiment in which the protagonist Norakuro serves. He is depicted as a bulldog, and his position is that of the regiment leader, holding the rank of captain.

In his role as the highest-ranking officer in the regiment, Colonel Bull is a figure of authority and discipline. When Norakuro first arrives at the barracks seeking to enlist, it is Colonel Bull who initially rebuffs him with a shout, stating there is no room for runts in the regiment. This introduction establishes him as a stern and no-nonsense commander, a portrayal consistent with his leadership role over the canine soldiers. Despite his gruff exterior, he is not without a sense of embarrassment; when an empty shell case falls on his head after his outburst at Norakuro, the commander is shown to be flustered, an event that ultimately leads him to order the non-commissioned officer to find work for the stray dog.

Colonel Bull serves as a direct superior and a key figure of authority in Norakuro's military life. The character's primary motivation is the leadership and operational success of the Fierce Dog Regiment, which frequently engages in conflicts with enemy forces such as the Monkey Army. He oversees the training and daily lives of his canine companions, including Norakuro, Deka, and Squadron Leader Mole, as they train hard together to improve their combat skills. His importance in the story is tied to the hierarchical structure of the army, acting as the commander who gives orders and maintains order.

There is no available information on Colonel Bulls personal background, how his character develops over the course of the series, or any specific notable abilities he may possess beyond his command authority. The available records confirm his species and rank but do not provide further details about his personality beyond the initial interaction with the protagonist.