When Mr. Audu says, "the MD is a witch and wizard rolled into one!", what figure of speech is this?

A metaphor is a figure of speech in which one thing is directly described as being another, without using the comparison words "like" or "as." When Mr. Audu says the MD is "a witch and wizard rolled into one," he is not literally claiming that the MD practises witchcraft. Instead, he uses this vivid image to convey that the MD is formidable, cunning, and perhaps intimidating - combining the negative qualities stereotypically associated with both a witch and a wizard into a single person.

This is not personification because personification involves giving human traits to something non-human, and the MD is already a human being. It is not an allusion, which would require a reference to a specific well-known person, literary work, or historical event. While witches and wizards appear across many cultural traditions, the expression does not reference any particular one. It is not assonance, which is the repetition of vowel sounds in closely placed words - there is no notable vowel-sound pattern in this phrase.