Kamen Rider: The Ancient Era

At first, Chuan Yuan thought he had transmigrated to primitive times.

Then the Gurongi began hunting his tribe.

Then his body was mangled because he hadn't fully developed the power of the incomplete Arcle belt, and only then did Chuan Yuan realize something was wrong.

This is damn well the world of Kamen Rider Kuuga!

Help! I can still lie low for a while!

Riku: “To protect my sister's future, I'll carry on Teacher Chuan Yuan's will and seal the entire Gurongi tribe!”

Godai: “To protect people's smiles, I have to choose to fight! Chuan Yuan-senpai, watch me transform!”

Chuan Yuan: Somebody save me first! I can still be rescued, I swear!

[Important notes]

The story will also travel back and forth to other Kamen Rider worlds, mainly the Kuuga and Agito worlds, with most of the story drawing on the Heisei Riders. The protagonist has cheat abilities, but isn't invincible, and grows stronger over time.