Volume 1(Prologue): Mistake

During the fight with Feldway, Feldway sent Rimuru at the end of time and space where he finds himself in state of misery because of thinking that he lost everything and everyone....

But Ciel suggested to that he can go back in exact time using the Time Leap and Nphility Collapse.

But there was a mistake happened, instead of going back in fight against Feldway. Rimuru was thrown back in time even more further which is......300 years before his Reincarnation by the interference of an unknown entity

(Ship of the story - Rimuru x Harem {Ciel, Shizue, Chloe, Chronoa and Luminous})