Unlike the others, Uni in terms of color and appearance while in HDD form resembles Noire almost exactly. Both wearing black with silver and white coloring with white hair. While Noire's eyes are glowing blue-green in HDD form, Uni as Black Sister has green eyes. When comparing the outfits, Black Sister has a lot more revealed in comparison to Black Heart.
However, it's worth noting that her chest has actually shrunken in size while everyone either stays the same, or grows. It's unknown what makes Uni's shrink.
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