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)
80 years have passed since Yuuki's defeat. Rimuru, after dwelling for countless years at the end of time and space, has surpassed Veldanava in terms of strength and is, therefore, the strongest being in the Cardinal world. With his strength, he easily dealt with the aftermath of the final battle and accomplished his d...