御子柴 夏子

One of Akihito's classmates. She is inseparable from Fuyuko, with whom she shares her humor. She and her friend are in perpetual hunt for finding a pretty and cute girl. 

They love to "touch" Umi, they find her very cute. Natsuko often expresses her desire to own Umi for herself alone. She even calls Akihito: "Akihito-oniisama".

It is quite difficult to determine whether her actions are real or just to joke. It is also impossible to really determine her real sexual orientation (heterosexual, lesbian or bisexual).

We can sometimes see some of the conversations she has with her friend, apparently their "hunt" is absolutely not fruitful this year.

She is one of the only girls who speaks easily with Oikawa, because she shares the same passions as him.