Tomoe is a classmate of Sumika and Ushio. The two don’t pay much attention in particular to her until they walk on her kissing her girlfriend, Miyako, one day after school (though they don’t realize the identity of the couple until later).
Tomoe and Miyako one day catch Sumika and Ushio “practicing” kissing with a plastic mask (an idea suggested by Ushio upon realizing Sumika has feelings for someone – though Ushio doesn’t know that someone is her) and draw the conclusion that they, too, are a couple. When they confront Sumika about the kiss, they learn that her feelings are one-sided. They still know, however, that Sumika and Ushio are interested in girls – and Tomoe seizes the opportunity to form a Girls Club, just for girls interested in girls. The two end up joining.
Tomoe is not in denial about her sexuality nor ashamed of it, and she and Miyako are unseperable. Once she starts hanging out with Sumika, Ushio and their friend Kiyori, however, she and Miyako confess that they never really were able to make friends because of their relationship and are grateful to be able to have fun with others as friends now.
Tomoe is straightforward and loud but not tactless, as evidenced by how her sensitivity towards Ushio’s family situation.