She's the student council president who studied Emperor Studies—basically grooming herself to be in charge. With British heritage (a quarter, anyway), she's got that mix of cultures going on.
The thing about her is that she's manipulative as hell. She managed to control a decent chunk of the student body and orchestrated this whole scheme to turn the school into basically a cult centered around the main character, positioning him as some kind of sacrificial figure for her ambitions. It's creepy stuff, honestly—the kind of villain move that makes you realize how dangerous someone with charisma and institutional power can actually be.
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