Matsuri first met Yuzu when they were little. Yuzu was a lonely child, and noticed that Matsuri was too, and thought they should be friends. Since then, they've become like sisters. Matsuri was very clingy with Yuzu, wanting to take baths with her and invading her house to sleep with her, and when Yuzu would go out with other friends Matsuri would demand Yuzu to take her with her. Matsuri likes Yuzu a lot, and became very jealous when she realized how Yuzu felt for Mei, trying to win her back but it fails it is revealed that idea of losing her "older sister" Yuzu to Mei simply scared her which led her to acting so wrong. After that, Matsuri acknowledges that what she was doing was wrong and realizing how Yuzu and even Mei cared for her feelings decides to be her friend and supports Yuzu's relationship with Mei. Matsuri enjoys teasing Yuzu, which makes Yuzu embarrassed. Matsuri realizes Mei never wanted to take Yuzu from her, and starts seeing Mei as an older sister too. and since then they been on good terms. As such, Mei tutors Matsuri with her studies from time to time, and Matsuri helped Mei win a prize at the festival.Even helping Mei get closer to Yuzu with the Summer trip, However after finding out about Mei's arranged marriage she became very upset and confused on whether or not Mei's been playing with Yuzu's feelings or if she truly does love Yuzu.
 Matsuri notes that Harumi is very suspectful, as she's always watching from far, which means she's afraid of getting hurt, and avoids conflicts. Matsuri says, however that she doesn't hate smart girls like Harumi.As time goes by Harumi starts to trust Matsuri to a degree that they're finally on friendly terms, as they are usually seen hanging out. Matsuri likes to tease Harumi, much to the latter's discomfort. It's possible she has a crush on Harumi.
She seems annoyed with her and her antics with her HaruYuzu fantasy. Despite this she is able to get along with her to a degree.
Mayu is a friend of Matsuri, who talked to her after her boyfriend dumped her. Matsuri comforts her, but her actions afterwards imply that she was the one to cause that.
They have a very casual relationship, with Matsuri being a regular customer in his cafe since she was little.
She seems to be intimidated by her.