Producer of Kamen Rider x Super Sentai Superhero War movie, S. Shirakura answered fan questions on twitter whether the returning Riders in this movie are the alternative universe characters from Decade, the originals from their respective shows or the urban legends from Fourze.

A fan contacted Shirakura via twitter and asked whereabouts do the Riders for the upcoming movie come from:

“By “parallel” do you mean that each one has their own independent world, like in Decade? If that’s what you mean, the series that would seem to occur in the same world, like Fourze or Gokaiger, would contradict one another, so we established a compromise.”

The fan asked, “So the Riders in Decade weren’t AU after all? So then, what about the Riders this time? Like, which Yusuke will be Kuuga?”

Followed by:

“It interferes with Fourze, which followed right in Decade’s footsteps with the past Riders existing as urban legends. The currently-airing show gets precedence, so we have to work at it.”

So it seems that they won’t be AU Riders from the Decade series, but ones from Fourze, which may or may not be the original Riders? Hopefully it’ll become clearer soon.