Mirrors of the Labyrinth (Kamen Rider Ryuki X Fire Emblem Fates) 

[Synopsis]

The grand battle known as the 13th Rider Fight had ended and peace returned once more or so they thought? An unknown thief called itself "The Creator" stole thirteen Advent Decks and tampered with it to create it's own version of the battle royale.   

Specifically selected thirteen people by the Creator to become Kamen Riders and setting by transported them to another world where the calamity war emerges between two kingdoms of Hoshido and Nohr. The new user of Kamen Rider Ryuki must fight to survive and stop the mastermind behind it all.