Don't mistake him for Satan, it's a fatal mistake
Em may be denouncing Illuminati/Satanism rumors that most mainstream artists are accused of. Although Shady referenced Satan earlier in this verse, he may be saying that it was only for the purpose of the paradox.
Or more literally, Slim shouldn’t be mistaken for Satan – he’s a rap god, though at the same time he isn’t exactly an angel either. His critics are more likely to say that he is a rap devil because of his perverse lyrics.
Em has also always had a dialogue with a deep-voiced Satanic figure — in “My Darling” and lately in the last verse of “Bad Guy”. It usually signifies Em’s inner demons. Ironically, this deep voice is also the voice of God in “Cold Wind Blows”.
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