Mai Tobita is a student at Miyaji Academy and is known as one of the first female friends of Emi Sendou. She shares her school life with Emi and shows a varying degree of interest in the card game Vanguard.

Mai possesses a shy yet sweet personality. She is not one of the most prominent fighters in the series, but her presence helps to broaden the circle of characters around Emi and shows the wider appeal of the card game within the school setting. As a student, she is a supporting figure within the group of friends at Miyaji Academy.

In terms of her role in the story, Mai is introduced as a friend who is becoming more involved in Vanguard. She is notable for being one of the first characters seen using the Neo Nectar clan, which was a new addition to the game at the time of her introduction. Her character reflects the wave of newer players picking up the game alongside the main cast. As the Link Joker season progresses, Mai does not take on a major role in the central conflict against the alien invaders, remaining largely part of the supporting cast and the broader community of fighters.

Regarding her abilities and deck, Mai's cardfighting style and strategy are defined by the clans she chooses. Her initial deck is primarily based on the Neo Nectar clan, which focuses on planting and growing units, with Maiden of Trailing Rose serving as her ace card. This deck also incorporates some Great Nature units. In the third season, she changes her deck to the Bermuda Triangle clan. Her strategy with this new deck centers on soul-building methods to fully utilize the Limit Break of her new ace, Eternal Idol, Pacifica, often in tandem with new PRISM units. One of her recorded battles is a loss against Emi Sendou. She also has a significant win against the fighter Naoki Ishida, demonstrating a moment of capability against a more experienced opponent.