From a series of plastic model kits produced by Imai, called Megaro
Zamac. There was never an anime show related to this series, I think
Imai simply produced the kits to cash in on the giant robot model craze.
From what I have been able to learn about the concept behind the model
series, the Run Valam is the main adversary mecha against which the Zamac
and the other hero mecha fight.
The pilot figure is a Daz/Poser pressure suit model created by 'Shukky',
everything else is my own work.