Genryumaru is one of the new Mashin born from the scattered power of Ryujinmaru in Mashin Hero Wataru: The Seven Spirits of Ryujinmaru.
Its design draws on the power of the Green Dragon and carries a distinctly ninja-inspired identity. That influence gives Genryumaru a different personality from the more straightforward heroic silhouettes elsewhere in the Ryujinmaru family. Sharp forms, concealed-warrior styling, and an agile visual language make it look built for speed, surprise, and precision rather than simply standing still and looking enormous.
Genryumaru emerges during Wataru’s journey to recover the broken fragments of Ryujinmaru. Like the other spirit-born forms encountered along the way, it represents one piece of the hero machine’s scattered power taking on a new form suited to the world and challenge surrounding it.
Official Sunrise staff have even singled Genryumaru out for the clarity of its visual character, with its ninja influence immediately readable in the design.
That is probably the nicest possible outcome for a giant magical robot.
You should ideally be able to tell what its deal is before it starts swinging weapons.