Mirei Minae is a blind teenage cardfighter and heir of the Minae family, leading Team Daybreak with the goal to conquer every Vanguard team in Japan. She crafts a cheerful, bubbly, idol-like public persona to attract members through popularity and kindness—a facade orchestrated by her legal guardian, Haruka to mask her emotionally troubled, antisocial nature.

Beneath this exterior, she battles profound loneliness and distrust, feeling consistently ignored or dismissed. Her lifelong blindness fuels deep-seated resentment when others treat her as vulnerable or patronized, amplifying her isolation. She misinterprets social cues, often perceiving remarks about her blindness as insults or assuming laughter targets her. Genuine compliments and sarcasm blur indistinguishably for her.

Her only meaningful bond was with her older brother, Nadatsugu Minae. After an incident led to his family disownment, a staged funeral deceived her into believing he died. Nadatsugu later returned as her caretaker under the alias Danji Momoyama, exploiting her blindness to avoid recognition. Discovering this truth ignited violent anger and betrayal, driving her to antagonize Danji’s friends despite their overtures. This cemented her distrust and fueled her resolve to succeed independently with Team Daybreak.

Despite her blindness, she is a cardfighting prodigy. She identifies cards by touch using textured stickers on sleeves and memorized every game card. An assistant narrates opponents' plays and card placements during matches, while her heightened hearing—honed to compensate for blindness—tracks opponents’ moves and overhears distant conversations. Loud environments overwhelm this sense, triggering hyperventilation.

Her arc centers on navigating betrayal, isolation, and the clash between her constructed persona and authentic self. The revelation of her brother’s deception catalyzes her antagonistic actions.