Brown operates as the primary partner and sidekick to the titular detective. He consistently appears as a small anthropomorphic dog with brown fur, a trait directly inspiring his name. His fur coloring resembles excrement, aligning with the series' thematic elements.

During investigations, Brown actively assists in solving cases, participating in evidence gathering and witness interviews. He often bears the brunt of unintended consequences from the detective's methods, particularly when caught by gas-based incapacitation techniques. This recurring dynamic establishes him as a comedic foil within their partnership.

In the movie "Farewell, My Beloved Partner (Butt)," Brown participates in the central mystery involving art forgeries and a secret society. A companion short film screened alongside this feature, titled "Movie Oshiri Tantei's Anything Crafts Club vs. Oshiri Tantei's Anything Crafts Club," prominently features Brown leading efforts to protect an art museum and painting contest from the antagonist Kaito U.

Beyond the main series, Brown's character extends into spin-off media. The publication "Anime Comic Butt Detective 8: Brown's Detective Class" includes a dedicated segment titled "Brown's Detective Class," indicating his role expands into mentoring or educational scenarios within the franchise.

His characterization remains consistent across adaptations, emphasizing loyalty and participation in collaborative problem-solving. The documented materials show no significant evolution or alterations to his core traits, backstory, or relationships.