Game Just Started: Book One by Cong Yi

Ever since a beam of light shot into the sky and someone obtained a Kamen Rider transformation device from within it, the world changed. Monsters began appearing everywhere, and a Battle Point System was added to the world's central hub.

Our protagonist is a household-name star. His parents died in a car accident when he was young, leaving him a vast corporate empire, a younger sister, and a fiancée.

His happy, if somewhat imperfect, life was shattered by the beam of light that burst from his body. No one knew what happened that night.

But from then on, no one ever saw his fiancée again, and a new figure appeared among the Kamen Riders, fighting for love.