The Seiken knight in the world of Tevyat (Genshin Impact x Kamen rider Saber)

Intro:

A knight named y/n is travelling with his brother to explore different worlds. However, they were suddenly stopped by an unknown goddess who captured his brother and cause the knight to lose most of the knight's power. The knight, now with the sword of fire and the sword of light explores the new world called Tevyet to find his lost brother. But he is not alone as he met a traveler named Aether who also encountered the goddess and lost his sister along with his companion name Paimon. Together, they will explore the world to find their siblings and regain their power.

Note:
I don't own Kamen Rider and Genshin Impact. They are owned by Toei production and Mihoyo respectively.

Also, this will be an ongoing story. So this story will be updated when I have created a new chapter.

Special thanks to @KR-Lupin for the book cover.