From what it sounds like, that change worked so well that Maleficent: Mistress of Evil will allow the pair to be even more effective in their battle against Michelle Pfieffer’s Queen Ingrith and her war against Maleficent.
Traditionally known as Diablo the Raven, the character of Diaval’s transformation in Maleficent allowed the role to not only take advantage of Riley’s talents as an actor, but also provided Angelina Jolie’s Maleficent with a more effective sounding board/agent of chaos.