I’m coming after whoever. Who has it?
He is being sarcastic. But the theme of the song is his drive and the temporary genius he possesses. The hook, “Ain’t no question if I want it, I need it” is descriptive of Kanye’s drive and motivation for brilliance; “I can feel it slowly drifting away from me” is a very telling follow-up. He tells us that genius and brilliance are temporary and transient in nature. That he believes, as the Romans did, that genius is something that somebody transiently possesses, not something that somebody is. This is very telling because it reveals him as less egotistic than what people make him. To admit that he only transiently possesses genius and is not himself genius, is a humble admission. In this line, I think he is both being sarcastic by saying he knows he currently possesses brilliance in his music. However, he is also saying that if he is wrong, and he doesn’t have “it” (genius), he has the drive to find out who does and defeat this person through hard work and perseverance. And it is the latter that jives with the overarching theme of the song.
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