This is my FAN_Made Teaser of the Next Kamen Rider movie, (After "Kamen Rider The First" and "Kamen Rider The Next") which I heard rumors could be base on Riderman.
So I used clips from the Kamen Rider The First Teaser trailer and Gackt's Riderman MV "The Next deacade".

Hopefully Gackt does play Riderman as he already has in the KR Decade Movie.
This is still just rumored though, but supposely it will called "Kamen Rider the Zero" and it will have V3 and Hongo find out that Shocker had created a prototype Rider before the First, a Rider Zero who's only upgrade was an arm. Now this Zero Rider ("Riderman") has broken free from Shocker yet has no memory of who or what he is, can The other Riders find him, before SHOCKER does? and what secrets does his arm lie?

I DO NOT OWN THE RIGHTS TO KAMEN RIDER, THIS VIDEO IS PURELY AS AN ACT OF FANDOM. (less info)