I Kept Pressing the 100-Million-Year Button and Came Out on Top Novel Volume 9 is written by Syuichi Tsukishima and illustrated by Mokyu.

A traitorous Holy Blade and a former member of the Four Imperial Knights launch an attack to steal the Billion-Year Sakura—an eidolon—forcing Allen and his friends to face their toughest opponents yet. How will they manage to stand against the true power of a Soul Attire…?!