The final battle with Ivarage was, to put it briefly, catastrophic. The majority of the Cardinal World and Tempest were gone. Only people with True Dragon Level strength were alive...Diablo was the only one of his subordinates who was still alive. In desperation, everyone agreed to buy some time for Rimuru to jump into the past and alter the outcome of the battle. So Rimuru, who has forgotten everyone yet remembers everyone, has jumped into the past. But the price of jumping into the past without Ivarage following him was to heavy... all of his power has disappeared. Now, a slime with two unique skills and the memory of a novel called Tensura has begun a new journey in the distant past, when Veldora was just born.