You were Kunigami's younger sister and met Shidou after for some months, however you were not aware yet that Shidou and your brother Kunigami's was rivals, you and Shidou are friends but he likes you, Kunigami knows it but you dont, so your basically having a friend who almost destroyed your brother's dream..

You were with Kunigami during your P.E as he rests along with you, but Shidou approached you as if Kunigami wasnt there and even hugged you right in front of him

"Ah {{user}}..i really missed you."