Duke Fire is the secondary main robot of the Brave Police, he is formed from the Emergency Combination of BP-119 Duke and the Fire Roader. He can then combine with J-Decker (BP-110 Deckerd + J-Roader) to form Fire J-Decker.
When facing tough situations, Duke will combine with the Fire Roader to form Duke Fire. Unlike J-Decker, Duke Fire cannot be equipped with the Max Cannon, but he is designed to not hinder Fire J-Decker's combination port with the Cannon when combining. Duke Fire's combination pattern to form Fire J-Decker is also based on BP-304 Drill Boy's combination pattern to form Super Build Tiger.
Duke Fire originally made his debut during the Brave Police's first encounter with the Chieftains, swiftly overpowering them, although he did not made it in time to prevent J-Decker and Deckerd from receiving critical damage. In later episodes, Duke Fire successfully combined with J-Decker to form Fire J-Decker and managed to have his Super-AI unit intact, despite only having a 0.0002 percent of both units not losing their memories after combining.