This robo papercraft is from gr-anime. Giant Robo is a manga by Mitsuteru Yokoyama, in which the huge robot of the same name as a title appears. Tokusatsu, Anime, etc. based on this manga were produced.
Since Toei requested a plot for Tokusatsu TV series from Yokoyama, he wrote this manga. Yokoyama made the setting "Giant Robo follows only a hero" for differentiation with his Tetsujin 28 which everyone can control.
About this papercraft:
Pages: Ins 7 + Parts 3