Pre-series
- Ancient history: The Grongi, a mysterious ancient civilization consisting of beings that can transform into monsters to kill people for their ruthless game, which is translated into the Grongi Language as the "Gegeru", attack their rival civilization the Linto. The original Kuuga defeats the leader of the Grongi and seals all 200 of the Grongi away.
- Ancient Rome: The thumbs up gesture originates as a form of approval in this period.
Series2000
2001
- January 1: Yusuke has an elaborate dream in which he celebrates the New Year while recalling his recent battles up to that point. (Ep. 46.5)
- January 20: Unidentified Life Form #4 (Kuuga) fights with Unidentified Life Form #0 (Daguva) in the city. (Ep. 47)
- January 29: (Ep. 47-48)
- January 30: (Ep. 48-49)
- April 27: The Unidentified Lifeform Related Cases Special Joint Investigation Headquarter is disbanded. (Ep. 49)
Post-series
- 2011: In an Alternate Timeline where Shocker conquered the world in 1971, Kuuga is among the Kamen Riders who reappear to defeat Shocker and its Great Leader. (Let's Go Kamen Rider)
- 2012: Kuuga is among the many Riders who apparently defeated by Captain Marvelous (Gokai Red), Emperor of Dai-Zangyack which seeks to wipe out the Kamen Riders, opposing Dai-Shocker led by Great Leader Tsukasa Kadoya (Kamen Rider Decade) who are hunting the Super Sentai. Infact, all the presumed deceased Riders and Sentai had been transported to the dimensional rift, from which they emerge to defeat the new Shocker-Zangyack Alliance. (Super Hero Taisen)
- 2013
- Kuuga joins in the battle against Space Crime Syndicate Madou's army of revived monsters. (Super Hero Taisen Z)
- Kuuga, among the first 15 Heisei Riders, is summoned to World within the Magic Stone, where he helps to defeat the evil wizard Amadum and his army of monsters. (''Wizard ep. 52-53)
- 2014: Kuuga participates in the battle to defeat the Underground Empire Badan, as well as the brief conflict between the Heisei Riders and Showa Riders. (Kamen Rider Taisen)
- 2015: In an Alternate Timeline where Shocker conquered the world in 1973, Kuuga serves Shocker before his brainwashing is reversed, joining the other Riders in the fight against Shocker before the timeline is restored. (Super Hero Taisen GP)
