Who Did Rimuru Summon?

Diablo is one of the main protagonists of That Time I Got Reincarnated As a Slime. He is one of the seven Demon Primordials, serving as the origin for the "black" demons. Originally a powerful archdemon, he was summoned by Rimuru, whom he pledges his loyalty to, evolving into a demon duke after being named.

Why does Rimuru summon Diablo?

Diablo is one of the primordial seven demons, known as "Noir", and Rimuru's strongest subordinate. Having been summoned by Rimuru during the former's ascension to Demon Lord status, Diablo desired to serve him in order to see the "truth of the world".

Who is Rimuru lover?

Among those children, Chloe becomes the one with the most affection towards Rimuru as she falls in love with him, even declaring she loves him though Rimuru didn't take that seriously initially but cares for her greatly even stating he wish she said that to him if she was 18 or 20 years older from now.