Sena, the daughter of the schools headteacher, is an attractive and academically successful individual who dislikes anything ordinary. Her arrogance leads her to be disliked by her female peers, despite their admiration eluding her. She treats male classmates as servants, although many would like to be more than that. Sena holds Kodaka to a higher standard and considers him the weirdest member of the club due to his unique personality.
Sena enjoys playing video games, including dating sims and eroge, which allow her to make virtual friends. Yozora calls her "Meat" (Niku) as an insulting nickname that she secretly likes. Sena's father is a friend of Kodakas father, and pulled strings so that Kodaka could attend St. Chronicas.
When Sena and Yozora fight, Sena usually runs from the room crying and shouting "Stupid Yozora! Go die!" It is hinted that she has feelings for Kodaka.
In volume 8, Sena proposes to Kodaka, asking him to marry her. Sena also confesses to Kodaka that she loves him.
In volume 9, Kodaka replies to Senas confession. He loves her, but due to the circumstances within the club, he is begging her to be patient. As long as the club exists, he doesnt want to go out on dates. Sena agrees and the club returns to the old status quo.
In volume 7 of the novel, it was revealed that Kodaka and Sena are fiancés betrothed by their fathers which she fully accepts.