Seiko Shinohara  

, 篠原 世以子

Seiko is an energetic girl who enjoys spending time with her friends. She may come across as immature or crass at times, making over-the-top outbursts that surprise those around her. Despite this, her close friendship with Naomi, whom she views as a kindred spirit due to their shared loss of a parent, remains strong. The two walk to school together every day and discuss their future plans. Although Seiko's more childish personality sometimes leads her to flirt with Naomi by fondling her breasts or commenting on her butt, Naomi tolerates these behaviors. It is heavily implied that Seiko harbors romantic feelings for Naomi, but she keeps these sentiments hidden from her friend, understanding and supporting Naomi's own attraction to Satoshi.