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Iori Kitahara (北原(きたはら) ()(おり) Kitahara Iori? ) is the male protagonist and one of the major characters of the manga series Grand Blue. He is a first year Mechanical Engineering student at Izu University and the older brother of Shiori Kitahara.



Iori is a blue-haired college student who sometimes receives remarks about being cute with a fairly muscular medium build.

Normally, his attire consists of a hoodie or jacket over a T-shirt. Throughout the anime, he was often seen naked with the exception of his boxers when he became intoxicated.


Iori was first depicted as a relatively normal boy just entering university who wants to lead a normal and peaceful school life. However, after joining the diving club, Iori spent most of his days intoxicated, naked, and partying with the club members until the end of the anime. He was rather unorthodox as well. While he was generally loud and boisterous through the whole of the anime series, Iori displays a kind and caring side as well, such as when he stuck up for Aina Yoshiwara when she was being picked on and how he defends Kouhei Imamura when he is insulted for being an otaku. Despite no initial interest, Iori comes to love diving and spending time with the members of the club, whom he becomes friends with and cares about despite their rambunctious behavior and endless crazy schemes.



  • Shiori Kitahara: Shiori is Iori's biological younger sister who have a rather complex relationship as Iori's general idiotic behavior left their parents to raise Shiori to take over the inn their parents run, much to her own displeasure as she wants to be free of the burden. Iori claims to know his sister well and he answers questions about her interests with confidence, but Shiori's inner thoughts shows that he actually knows very little about his sister. Nonetheless, Iori is well aware that she does not want to take over the family inn and encourages her to tell their parents. Deep down, Shiori is a bit of a bro-con and cares for Iori despite her annoyance to his stupidity and refusal to succeed their parents.
  • Toshio Kotegawa: Although very briefly, the relationship between the two was full of Iori's disbelief at his mannerisms and general way of thinking, as Iori became used to his surroundings, he began to develop a much stronger relationship towards Toshio.
  • Nanaka Kotegawa: Due to Iori's father being originally adopted, she and Iori are not related by blood. Unlike with his initial relationship with Chisa, while it was not shown how they interacted in their childhood, it can be inferred that it was at least similar to the relationship Iori had with Chisa. Currently, they have a fairly happy and pleasant relationship. Nanaka looking after Iori like a little sibling and caring about his wellbeing. While Iori cares about her in a very similar manner, despite admitting he finds Nanaka very attractive. Despite Nanaka's fanatical love for Chisa, over the course of the series, she comes to view Iori as an acceptable boyfriend for her little sister. This, however, does lead Nanaka to become incredibly protective and watchful over Iori's love life. Refusing to let him stray away from her beloved sister, and wanting to make sure Iori protects Chisa from flirty people as much as possible.
  • Chisa Kotegawa: The same as her elder sister, she and Iori are cousins unrelated by blood and were childhood friends a decade before the start of the series. Not much is known about her childhood with Iori, however, it can be inferred that they were fairly close with one another from the shot of the two running with each other along the beach shoreline that we are shown. This being said, however, their reunion as college students was anything but smooth. Their very first "meeting" was Iori getting a passing by glance at Chisa while she changed out of her diving suit after getting out of the water. Leading to the two have an awkward staredown before Chisa gave Iori a puzzled look and Iori simply continued to walk off on his way. Afterward, their first "official" reunion didn't go any better, in fact, it went far, far worse. Chisa walked into the Grandblue shop eager to meet her cousin again after over a decade apart, only to find him stripped down to his boxers and dominating his fellow Peek-a-Boo members in a drinking match. This led Chisa to gain an immediate disgust in what her cousin had seemingly become in their adulthood. Proceeding to write the young man off like an idiot, going as far as to say "I never imagined you'd grow up to be so stupid." Presumably wanting nothing to do with him anymore, she smacked away his hand as Iori attempted to greet Chisa by placing a hand on her shoulder, and taking off the jacket she was wearing and urging her sister to burn it before slamming the door behind her as she went to her room, much to Iori's bewilderment and sorrow at this misunderstanding. This, however, was far from the end of their interactions. Over the course of the time, Iori spent living in the Kotegawa household, he began to slowly but surely mend the rift he inadvertently created between the two cousins. Getting caught up in each other's (mostly Iori's) initially comedic antics, Chisa still wanting to show her cousin the wonders of the ocean she loves so much, Iori getting fully invested in said world, the two becoming "Pretend boyfriend and girlfriend", and many more experiences lead the two to somehow form a strong and caring relationship. The time spent living together leading the pair to almost become in sync with one another when performing tasks like cooking, and very much having the interactions of siblings or an old married couple, much to Chisa's declarations that Iori was stupid. This relationship created an almost unspoken mutual trust between the pair. Iori coming to Chisa for help with his diving practice, Chisa never hesitating to lean on her "Boyfriend" whenever someone tries to flirt with her. It can be said that Iori and Chisa have come to care about each other's wellbeings quite a bit. Iori not hesitating to put his life into danger when he thought that Chisa had fallen down a cliff in a drunken stupor, Chisa always making sure Iori is enjoying himself and being involved when they go out diving(which is sadly not very often.), and seemed genuinely concerned for her cousin's emotional state when he was left out of diving for not properly obtaining his license, and Iori even going as far as to miss his flight back home to stay behind and figure out the mysterious case of Chisa's mother's hearing. (Although this can be argued to not be his original intention as Iori himself stated he simply stayed behind to get back the pornographic magazine he forgot.) This led Chisa to give Iori a genuinely heartfelt and tearful thank you after Iori came to her in the middle of the night to clear up the misunderstanding involving Chisa's mother. (which had previously been tearing Chisa up on the inside.) Leading the young woman to tell her cousin "I'm so glad you're here!", the warm gratitude on Chisa's face leading Iori to blush as he was caught off guard. The case of Chisa and Iori's relationship and whether or not it could ever be romantic is hinted at and visited multiple times throughout the series, despite the two dismissing the idea seemingly whenever it's brought up, such as Iori saying Chisa's like a sister to him, and Chisa simply calling him stupid. However, with the two seemingly becoming closer and closer the more the story continues, and subtle hints being dropped every so often about their feelings for one another, it can be stated that while they currently might not have any romantic feelings for one another, it's entirely possible that said fact can be subject to change in the future.

Peek-a-Boo members:[]

  • Kouhei Imamura: Iori's fellow classmate and club member. Their relationship begin with a rough start with him being swindled by Iori into joining Peek-a-Boo against his will. Despite this, lori and Kōhei were able to get along just fine though they were at each other's throats due to their initially eccentric and silly antics. They are best friends.
  • Shinji Tokita: Iori has a strong bond with his senpai, Kotobuki and Tokita. They often joke around and both sides are interested in learning more about each other. First meeting each other when Iori stumbles onto their naked rock, paper, scissors games twice. Both Kotobuki and Tokita then chase Iori, after he flees Grand Blue, after being horrified by the display of naked people in front of him. Their friendship blossoms into Iori joining in on the naked fun.
  • Azusa Hamaoka: Iori's relationship with Azusa is a strong sister-like bond, with Azusa making inquiries about Iori's love life, especially towards his "crush" on Kouhei. Iori thinks of Azusa highly, with Azusa reciprocating, this was shown by Azusa offering to sleep with Iori, in order to make him less nervous around herself and Nanaka.
  • Aina Yoshiwara: Iori took revenge on Tinkerbell for Aina. Since then, Aina has developed a one-sided love for him, but he has yet to realize this. He nicknames her "Cakey" as she often puts on horrible makeups. Iori sees Cakey as another dorky friend, much like Kouhei.


  • Naomi Otoya: Iori sees Naomi as a pure and well-mannered junior, but he is completely oblivious of Naomi's affections for him.
  • Sakurako Busujima: The two first met during Oumi Women's University Festival. At first, Iori did not have a good impression of Sakurako. As she openly ridiculed Kouhei's hobbies, Iori dumped beer on her head. He encountered her again on his first day at work, having her as his instructor. Then the two start a series of mutual bullying, where Iori is often on the receiving end. Their relationship at work is like that of master and slave.
Iori cheered Sakurako up after she got rejected by Naomi. Since that day, Sakurako has developed romantic feelings for Iori, while he is not aware of that yet.

Sakurako kissed Iori during his second trip to Okinawa Island.[1]

Sakurako kissing Iori.



  • The name Iori means "that one" (伊) (i) and "weave, weaving" (織) (ori).
  • Iori's surname Kitahara means "north" (北) (kita) and "field, plain" (原) (hara).