A bored Rimuru Tempest accompanies Diablo when he goes to meet with an old friend in the Netherworld. What will happen when he meets an out-of-place human boy who piques his interest? (Tensei Shitara Slime Datta Ken and Mairimashita Iruma-kun crossover)
It has been 12 years after the Great Tenma war. Rimuru is ever-busy with the reconstruction of his capital, the treatises between nations, and his harem. On a date with one of his subordinates, a mysterious magic circle forms beneath them, and they get summoned to another world. Only to find out, he was summoned compl...