The protagonist travels through the world of Kamen Rider Sword. On the eve of the extreme war, he takes the entire laboratory that stores cards and Kamen Rider system data and travels to the Demon God War period in the Teyvat continent.
In order to survive, he studied hard and spent decades modifying himself into the second joker, and entered the dormant cabin to wait for the travelers. However, an accident unsealed all the undead creatures. An extreme war without a referee is about to begin.
