J-Decker is a super robot from the Brave Police J-Decker series.
J-Decker is the combined form of Deckerd and J-Roader. He is capable of flight and wields a variety of weapons including a blaster, and can also link with and operate the Max Cannon, the combined form of Gun Max and Gun Bike. Fire J-Decker is the combined form of J-Decker and Duke Fire.
When Deckerd first attempted to combine with J-Roader, he ran into issues due to his coding changing when he gained self awareness. With Yuuta's help, he was able to overcome these issues and combine to beat Barbarossa, a magician using an air force to attack Japan. J-Decker usually was used as a last resort against monsters too large and powerful for the Brave Police to bring down by themselves, and often in conjunction with Super Build Tiger. Later, J-Decker often would combine with Duke Fire to form Fire J-Decker.