Kamen Rider a

Urataros has trailed the past Daiki, who I should mention here wears a hat and dresses similarly to Daiki at the beginning of Decade, although it's questionable if it is supposed to be a pre-series Daiki, given what happens later. Then again, Daiki stomps all over his own time line in this movie and doesn't end up as his own grandfather or anything (I think) so it all works out, somehow.