Masaki is the main female lead of Mayoiga and one of the thirty passengers on the bus heading to Nanakimura. She's a 17-year-old student with a genuinely bright and earnest personality—though she has a bit of an issue with mysterious girls, which comes up more than once.
What makes Masaki interesting is how odd she can be. She's pretty stubborn about her own beliefs and sticks to what she thinks is right, even when it doesn't always make sense to others. There's something hinted at throughout the series suggesting she might have some kind of ability to see or sense future events, though it never gets explicitly confirmed in the actual episodes. Fans have speculated about this more than the show itself clarifies.
She's genuinely emotional and prone to random outbursts—the kind of person who'll suddenly question whether she's losing it, like when she asked Mitsumune in episode 1 if she was "off her rocker." She also gets motion sickness pretty easily, which is just one more thing that makes her feel like an actual teenager rather than a polished character.
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