After achieving peace Rimuru was stuck doing paperwork for the last few centuries and was stuck with boredom. Ciel seeing her master's state suggests going back in time to the era when Veldanava created the cardinal world. I don't own Tensura. I adjusted the story to my liking. English is not my main language so don't bother about grammar mistakes too much If you guys want to read advanced chapters go to my Patreon account. patreon.com/Nauty_Manu