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Yamaguchi Iyo (山口 賢二?, lit. Iyo Yamaguchi) is the younger sister of Kenji Yamaguchi. She first appears as a first year student in Syoyo High School. Iyo appears as the story's extended antagonist later main heroine or good character.


Iyo Yamaguchi

Iyo's full appearance.

Iyo is a very cute girl of tall, slender figure. She has short blonde hair cut in a style similar to her older brother and brown eyes. When not wearing her uniform, she is always dressed fashionably.


Iyo always refers herself in the third person. She is a rather vain girl, often commenting that she would be a better girlfriend than Shizuku because she is cuter. When she first met Haru, she immediately thinks he's handsome and cool. Though she gets jealous, she knows to hold back sometimes, and does not hate or dislike Shizuku personally. She often tries to give Shizuku tips on how to be more fashionable. 


Iyo was seen walking into school when Shimoyanagi accidentally bumped at her. She saw the 2nd years looking at him and was asking herself if they like her. Natsume saw her sighing all alone and greeted her. She immediately complimented Natsume as a kind person and as being much cuter than herself, making her somewhat jealous.


Yamaguchi Kenji Edit

Iyo at first seems afraid of her brother, saying to Natsume that "an older brother is a person who denies his sister's existence down to the roots". After meeting him in the Doughnut shop she immediately ran away. Though they don't have a good relationship, they still care about each other, as seen in volume 13 of the manga when Yamaken drags Iyo away from her date with Yūzan because he thinks that Yūzan is a womanizer and Iyo wishes for Yamaken to find his own true love. Though the reason for Iyo's fear of her brother is never revealed, it seems safe to assume that Yamaken may have bullied her when they were younger if people payed more attention to Iyo than to him or if she was better than him at something, as he was seen doing this do Haru.

Natsume Asako Edit

Natsume saw Iyo sitting alone and sighing at school. Remembering how she once hid somewhere alone, wanting someone to notice she was gone and come looking for her, she decides to ask Iyo what's troubling her and if she can help. Iyo is immediately taken with Natsume, commenting that she's even cuter than herself, calling her Asako-senpai and telling her how kind and cool she is. Natsume is likewise taken with Iyo, determining to take her under her wing and always be available to help and protect her when she needs it.
Ptonari 013

Natsume protecting Iyo.

Yoshida Haru Edit

Haru mostly ignores Iyo, seeming to only think of her as Yamaken's sister. Iyo, on the other hand, had a crush at first sight towards Haru, and had tried getting Haru to notice her more than Shizuku at times.

Mizutani Shizuku Edit

In the manga, Iyo was initially antagonistic toward Shizuku, as Haru said that he liked Shizuku when Iyo asked him if he had a girlfriend. She would frequently try to get Shizuku to reject Haru, often making comments about her perceived superiority over Shizuku, such as "Iyo is much cuter than you!" and "If you two breakup, give Haru to Iyo!" over and over. After meeting Yūzan and seeming to fall for him, Iyo steadily seems to loose interest in Haru. They remain friends.

Yoshida Yūzan Edit

In the manga, Iyo first sees Yūzan when the group goes camping, and thinks he is even more handsome than Haru. Not knowing that he was Haru's brother, she later daydreams of Yūzan and laments that she'll probably never meet him again. When Yūzan is later introduced to her as Haru's older brother she tells him she likes him, and Yūzan is surprised to realize he likes her too, then is shocked to realize he likes a girl younger than his little brother. In volume 13 Iyo bumps into Yūzan again by chance and asks him on a date as a prerequisite to marriage, to which he agrees despite his fear and distrust of women. While she initially liked him because she thought he was even more handsome than Haru, the date goes very well and they find they actually have a lot in common. Unfortunately the date is ended early when Yamaken sees them together and drags Iyo away.

Trivia Edit

  • Her blood type is A.
  • Just like her older brother, she has an excess of self-confidence.
  • She is unexpectedly a very self-disciplined girl.


  • (To Haru and Shizuku) "Oh... Um... Haru-senpai, Shizuku-senpai. Sorry for my misconduct just now... Please somehow, forget about today."
  • (To Natsume) "Asako-Senpai, living beings called brothers are entities that denies the existence of their younger sister from their very roots."