Kamen Rider: Ryuga

This book is also known as "The Beginning Cutoff by Shinji Chengo and Transformed into a Dragon Rider", "Kamen Rider: I Can Stack Q Infinitely", "Kamen Rider Starts Cross-Pushing from Ryuga"
Shinichi traveled through time, but he was not very happy, because he clearly had the golden finger Soul Bash (Dog Head Q Technique) (can) but can't use it, because his golden finger needs to kill extraordinary creatures to be effective, but he didn't find extraordinary creatures after traveling through time, which is very difficult, not to mention that he is an ordinary person and he can't run away when there are monsters. If he wants to kill the monsters, he can only sneak attack.
A few years passed in this hazy state, until one day he came to Tokyo.
I saw a man in a black trench coat taking out a black box, shouting "Transform" at the glass wall, and then wearing armor and getting into the mirror...
At this time, Shinichi didn't know that he had traveled to Kamen Rider Ryuki, "Grass"
Note: The protagonist Goldfinger's power is immune to the reset of the timeline.