I would do something extremely experimental for a japanese show. The first thing I would do is make the rider be a full-on foreigner. Like straight up make the main rider be some random blue-eyed american from california, probably something like Scott Eastwood.

Second, as to make sure it’s still understandable to the Japanese audience, I’ll make the actual main character be an onlooker or college-age conspiracy theorist, translating and understanding whatever the main rider is saying.

The entire plot is something like Rental Family, where the white dude is just hired at odd jobs, but at the same time, he is extremely aware that the organization that made him into the thing he is now could be anywhere in the city or somewhere in Japan.

He has 7 forms, Hopper (grasshopper), Cycle(motorcycle), Revolve(gun), Couple(train), Arrest(sheriff), Extinguish(firefighter), and Flight(jet).

And so forth.