EnRyuu, designated model number GBR-3, is a Super-AI Vehicle Machine created by the Earth defense organization GGG as the twin unit to HyouRyuu. He transforms between a firetruck vehicle mode and a humanoid robot mode, embodying a fire-based motif consistent with his name meaning "Flame Dragon." His personality contrasts sharply with his twin, marked by impulsiveness, brashness, and a tendency to act without forethought, leading to disagreements. A notorious operational difficulty involves executing proper landings after aerial deployments, often resulting in crashes; this improves over time with experience and after receiving a power boost from Mamoru Amami that stabilizes his System Change transformation sequence.

In robot mode, EnRyuu employs several weapons: a multi-purpose Power Ladder extending for utility or combat use as a tonfa; a Melting Gun, later upgraded to fire Ul-Tech beams; a Mirror Coating Shield that absorbs and redirects energy attacks; a Chest Warmer unit; and a Pencil Launcher firing solidifying gel bullets for containment or structural support, compatible with both EnRyuu and HyouRyuu.

His operational history includes participation in GGG's battles against extraterrestrial threats, notably during the EI-06 incident, where he demonstrated adaptability by using his ladder to rescue a falling elevator during one of his crashes. His core tactical function is Symmetrical Docking with HyouRyuu to form the combined robot ChouRyuuJin, integrating his shield as ChouRyuuJin's chestpiece. He also achieves Cross-Symmetrical Docking with FuuRyuu to form GouRyuuJin. During the 31 Machine Primevals invasion, his Super AI unit was loaded into the upgraded Star GaoGaiGar alongside other GGG units, expanding his role in combined operations.

Trivia notes his AI completion timestamped at 14:25:16, making him five seconds younger than HyouRyuu.