Responses
From a genetic standpoint she could just possess two recessive alleles that resulted in her having black hair. Think when a blonde child is born from two brunettes. But since it is a manga then it's probably just the power of plot lol.
I forgot genetics could play a part lol
I love it when cute MCs dominate the hearts of everybody. And is there an answer to why her hair is black/brown instead of red or white? Or is that just the power of plot?