4 Primordials Demon is four ancient demons in Tensura series that served as Rimuru's subordinates. There's Diablo, Carrera, Testarossa, and Ultima. Diablo is the black primordial, he was calm and act like a butler, but will mad when someone insult Rimuru in front of his face. He was extremely loyal. Carrera and Ultima, their acting more childish and didn't get along with each other, but this two still strong. Testarossa behave like typical noblewoman. Gentle and elegant.