Kamen Rider 15

After Daiki shoots at them a bit, Momotaros remembers him as "that robber guy". We never get any flashbacks to prior movies/episodes like in Episode Blue, but we can just assume he's talking about Decade #14 & 15, and any subsequent meeting they've had. At this point, don't even try to bring in the concept of alternate universe Den-O's any more. The Chô Den-O Trilogy has basically taken any hope of that, doused it in kerosene, and lit a match. Not that I mind though! It's all one big happy thing and it pulls in Decade, Kiva, Ryuki and whatever the hell else it feels like. You could probably go as far as to say that Dragon Knight and the stage shows are all viable ground too.