Rombiako (31):A monster from Sound World, Rombiako arrives to feed on noises, increasing its size. He takes a nap before it feeds again and the cycle repeats until it's too big for the world to hold. His meter would go up in blue when there was noise to make him big and the goal of both the Go-onger and Gaiark was to lower down in the red. The only means to shrink it is with beautiful feminine sound, which Rombiako hates and goes on a rampage at hearing upon hearing, evidence by a bell system that sounded like a woman's voice. In the end, the monster is stopped by the specially assembled G3 Princess group (Renn, Miu, and Kegaleshia) who shrink him and kill him with their attack.
- Height: 5 cm to 200 m
- Weight: 600 kg to 2100 t