Rasen no Emperoider Spin4.: Fallen Empire

is the fourth volume of the Rasen no Emperoider light novel series, written by Kouhei Kadono and Illustrated by Eiri Iwamoto. It was released under the Dengeki Bunko Imprint in January 2017.

Synopsis
The battle for the Emperoider goes to the final stage-who will be the last to stand at the end of the battle ...?

Have you ever thought "this is the end"? I, Saiga Kousuke, always feels like that. The future is closed and I don't think I can do anything. But the world says we have to do this and that. To be honest, I'm sick of it. I'm sure we have to conquer the world to avoid being forced to do what we can't do ... The battle for the mysterious Emperoider enters the final phase. The inevitable ruin opens when people gather in the "Fang Scars", the land of all origins. The reconciliation mechanism is powerless, the miraculous messenger is confused, the shadow emperor is destroyed, the strongest warrior loses his way, and even the queen of nothingness despairs. Who is standing to the end when the spiral draws a whirlpool ...? The story of the battle over the "King of the Spin" Emperoider presented by Kouhei Kadono and the newly written "introduction" were added, and it was finally completed.

(source: Bookwalker JP - Translated)