It's been 80 years since Yuuki's defeat. Rimuru after dwelling for countless years on time and space, has surpassed Veldanava in terms of strength, And therefore being The strongest being in The Cardinal world. With his strength, He easily dealt with the aftermath of the final battle And finally accomplished his dreamed of coexisting monster's and humans. Although he is happy with the results, his daily routine consists of constant paperwork. During one of these boring days Ciel, who is worried about the mental state of her master, suggests creating an alternate Timeline and traveling back in time. Rimuru, not wanting to do everything over again, comes back with an alternative idea. Going back in time but with one addition: instead of traveling to his original time of reincarnation as a slime, he decides to go much further in time and become one of the ancient demon lords. (A/N:The original author of this story is, Mert_Dertli. However he stopped working on the novel at chapter 4, Which was quite sad he have a good story that's why, I copied about 2-4 chapter of the original book. So that's why I will continue this work, If you are the author please contact me I will definitely dropped this if you don't want it)