Result of Fusion between a Soldato J-series cyborg and J-Bird (the upper, separable component of J-Ark which contains the bridge and dorsal Anti-Meson Cannons). After Fusion occurs, the J-Bird must "Plug Out" in order to transform into J-Der (or King J-Der). It is equipped with Double Plasma Swords. J-Der can "half-dock" within the main body of J-Ark, leaving its upper body in robot form while its legs remain in J-Bird form. This creates J-Rider Mode, allowing J-Der to utilize J-Ark's power and speed at the cost of J-Der's own maneuverability.