Thank you very much for this helpful explanation! Based on what you've said, it seems like it would make sense to approve your nominations as "Kamen Rider Heisei Era" or "Kamen Rider Heisei Phase One" (if characters who are a substantial part of the plot in Kiva also appear in Decade in a significant capacity as the character travels between universes) and "Kamen Rider Zi-O" (since even though Kiva is referenced and Jirou appears, the connection is more tenuous). Does that make sense?