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'The someone' could be referring to Hatsune Miku being portrayed with black hair and black clothing, or they could be mistaking her for Zatsune Miku or Black Rock Shooter.
- Zatsune Miku is a derivative based on Hatsune Miku. Her hair is black and her eyes are red.
- Black Rock Shooter is not a derivative of Hatsune Miku. Her hair is black and her eyes are blue.
- Black Miku is a term by Japanese fans who use it as a general term for Miku when she is portrayed with alternate colors.