She is a fellow classmate of Shinji’s, and tries to stop the brewing fight between Shinji and Toji over the latter’s sister. She is also the class representative.
While Shinji is wondering about Rei, Toji thinks he might be perving on Hikari. When Shinji uses Toji to get an emotional response from Rei, Horaki calls Toji a moron.
Asuka invites Hikari over to Kensuke’s celebration of Misato’s promotion and Asuka’s moving in with Misato and Shinji, thinking that Shinji, Kensuke and Toji would be lame company. She brought flowers in congratulations for Misato’s promotion. Hikari later keeps Toji and Kensuke back in school, giving Shinji Rei's homework and asking him to give it to her due to the girl's absence.
She is later at school, and finds Toji trying to peek up her skirt. She tries to grab him but he runs, falling down the stairs with Shinji. She notices Shinji bleeding and takes him to the infirmary. Whilst there she quizzes Shinji to find out if Toji likes her or talks about her. When Shinji tells Asuka about this, she tells him that it’s because Hikari likes Toji.
Hikari is later pulled aside by Asuka to talk about her feelings for Toji. At Shinji’s suggestion, she decides to make him a lunch. When she meets to give him the lunch she made, Toji tells her that he’s going somewhere and that he’d like to try being friends when he returned. When she speaks with Shinji later, she seems happy about Toji’s suggestion. She is later seen preparing Toji another lunch, unaware that he has recently been killed during the Eva 03 incident.
Hikari appears in a dream Shinji has while in the hospital, asking after Toji.
When Hikari appears again, she sees Shinji speaking with Kaworu outside the school. She’s happy when he runs off, knowing that things have changed to such a degree that they wouldn’t be like friends again.