Masumi represents the Leo Institute's Dueling Fusion Summon course and pilots a Gem-Knight Deck. She's known for being direct and outspoken—she doesn't sugarcoat her thoughts or hold back what she believes. Part of this comes from growing up around her father's jewel appraisal work, which seems to have given her an uncanny ability to read people. She can spot talent and weakness in someone just by watching them, something she demonstrated pretty quickly when facing off against Yuzu.
Her sharp tongue might come across as mocking, but she's generally calling things as she sees them rather than just talking trash. There's real observation backing up what she says. Beneath that blunt exterior, though, she's genuinely caring—she values her friends and her teachers deeply. When Professor Marco disappeared, she became genuinely distressed trying to track him down. She's particularly protective of Marco and clearly thinks highly of him, enough that she won't tolerate anyone disrespecting him.
Content compiled by AnimeList.moe from publicly available sources.
