第1章 原始开局x大逃杀开局

Original Start x Battle Royale Start

At first, Kawahara thought he had traveled to the primitive age.
Until Gurongi began to hunt his tribe.
It was not until his body was tattered by the incompletely developed Aguru belt that Kawahara realized that something was wrong.
This is the world of Kamen Rider Kuuga!
Help, I can still survive!
...
Riku: "In order to protect my sister's future, I will carry the will of Teacher Kawahara and seal all the Gurongi clan!"
Godai: "In order to protect people's smiles, I must choose to fight! Senior Kawahara, please watch my transformation!"
Kawahara: Save me first! I really can still save it!
...
...
[Key points] 
I will also travel back and forth to other knight worlds, mainly in the worlds of Kuuga and AgitΩ, and mostly in the stories of Heisei knights.