Rimuru visits the otherworld.

After the Great Tenma War. Peace has been gained in Cardinal World.
100 years later. Seeing that Tempest became the absolute ruler of the Cardinal World. Rimuru decided to take action that he's been put on hold, and that's fixing the other universe. Though he restore the universes that have been destroyed, it can't be said that it returned to normal. He also uses this as an excuse to take a vacation.
Let's go on an adventure with Rimuru taking a vacation.