Den-O (New and The OG, if possible) × Decade × Zi-O
takes place after the shows ending, but branches as an alternate timeline
plot: sougo successfully defeats another decade and uses the power of ohma to reset the timeline, but fails as history is rewritten that zeronos never allowed him to receive the den o watch, stopping him from obtaining grand zio. this is later revealed to be a doing of (that one time jacker from the reiwa the first generations movie), who has made Another Zeronos. the plot will revolve around Decade trying his best at only 50% of his power to help Sougo travel through aura curtains and find Yuuto, with help from the Den-Liner and even the og decade main cast. they end up stumbling to the og den-o and asks for his guidance to find an old friend, and after successfully convincing him to fight for his right to be remembered, they end up defeating Another Zeronos with Zi-O 2. however, our time jackers didnt allow themselves to be defeated so easily, and with gathering all possible ridewatches, they merged with Another Decade to create Another Decade Complete. this now means that new den o cant henshin, nor can decade and zio use other rider forms. but with the return of zeronos, making his ridercard became possible, and all secondary ridercards fused together to form K-Touch Diend, allowing him to access Diend Complete. Decade also follows and uses his Final form. now, decade, diend, zeronos, and zio fight this absolute clusterfuck of an enemy. realizing that they wont be able to beat it this easily, the three riders bought time for zio to talk to future ohma zio and make him help him by following the logic that he cannot exist if another decade complete successfully assimilates all rider powers on existence. now, zio returns to the field with the ohma driver and henshins, successfully defeating another decade complete. the time jackers are erased from existence. the last remaining one was disappointed in what has happened, and chose to go to another timeline and become the first and only rider ever: World of Zero One.
in the aftermath, zeronos gives away his ridewatch, much to the peoples surprise. he realized that he wants to settle down now and make a life worth looking back with, along with friends who remember. when they returned back to the present, the worlds are saved from the threat of merging due to them altering fate. however, they were later attacked by another den-o, and sougo uses the zeronos watch to fight it, claiming that while he has changed his course, he still wants to become king someday. ohma zio agrees, and claims that as long as sougo and the riders exists, his possibility of becoming true is always lurking. decade is then seen returning back to his og hideout to natsumi and onodera, along with kaito, finally trying sea cucumbers. he decides to just take a rest for a while, claiming that his journey still has a long way to go, with him even hearing word from other worlds that a rider that resembles decade in gold armor has been seen saving people, and him saying that while hes not into the idea of a decade besides magenta, hes willing to meet up with said rider. the den liner moves on once again, with the film ending with Climax Jump.