Hokuou Bishoujo no Classmate ga, Konyakusha ni Nattara Deredere no Amaama ni Natte Shimatta Ken ni Tsuite Volume 5 will be published in Japan on August 25, 2026.
The latest book by Karui Hiroshi, illustrated by pon, introduces Akari, a girl claiming to be Tooru’s younger sister. Her openly possessive affection adds another participant to the increasingly busy romantic life surrounding Tooru and Aino.
Quick Summary
- Japanese title: 北欧美少女のクラスメイトが、婚約者になったらデレデレの甘々になってしまった件について
- Romanized title: Hokuou Bishoujo no Classmate ga, Konyakusha ni Nattara Deredere no Amaama ni Natte Shimatta Ken ni Tsuite
- Official English/global title: not announced
- Format: light novel
- Latest installment: Volume 5
- Genres: romantic comedy, school romance, cohabitation, and harem
- Author: Karui Hiroshi
- Japanese name: 軽井広
- Illustrator: pon
- Publisher: Hifumi Shobo
- Imprint: Brave Bunko
- Release date: August 25, 2026
- Price: 935 yen including tax
- Base price: 850 yen
- Format: bunko, approximately 103 × 148 mm
- Page count: 240
- ISBN: 978-4-8240-0737-1
- Cover character: Aino Lyuty
- Protagonist: Tooru Renjo
- Primary heroine: Aino Lyuty
- New Volume 5 character: Akari
- Akari’s claim: she is Tooru’s younger sister
- Other characters: Chika, Asuka, and Ririka
- Main conflict: Akari enters the competition for Tooru’s affection
- Manga adaptation: ongoing
- Manga artist: Takeshi Kagura
- Original character designs: pon
- Manga Volume 1: released December 25, 2025
- Web novel: completed
- Web episodes: 93
- Award: Silver Prize at the 2nd Hifumi Web Novel Award
- Official English edition: not announced
- Official Indonesian edition: not announced
- Anime adaptation: not announced
- Printed-book age rating: not listed
- Web version tag: R15
Official Announcement and Volume 5 Cover
Aino Returns in a Domestic Cover Scene
The Volume 5 artwork once again places Aino Lyuty at its center. She is shown holding chopsticks and food with a soft, embarrassed expression.
Her white-and-blue clothing preserves the visual identity of the blonde, blue-eyed Finnish heroine.
Rather than focusing on conflict, the illustration emphasizes the comfortable domestic life that has developed between Aino and Tooru since their engagement.
That calm appearance contrasts with the story inside the book, where Akari’s arrival disrupts the romantic balance of their shared home.
Akari Claims to Be Tooru’s Younger Sister
Volume 5 introduces Akari, a girl who suddenly appears before Tooru and identifies herself as his younger sister.
She is not interested in maintaining a purely familial distance. Akari directly declares her love for “Onii-chan” and shows a strong desire to keep his attention for herself.
Her arrival surprises Aino and the other residents. Tooru is already surrounded by his fiancée, a former fiancée, and two maids with close personal relationships to him.
Akari immediately becomes another participant in that dynamic. Her confession opens a new stage in the competition surrounding Tooru.
The prerelease synopsis does not completely explain why Akari calls herself his sister or reveal their full shared history.
Aino Faces Another Direct Rival
Tooru and Aino originally became engaged because of their families. What began as an arrangement gradually developed into genuine affection.
Although Aino appears confident and almost perfect at school, she is privately shy, lonely, and eager for Tooru’s reassurance.
Volume 5 challenges that increasingly stable relationship. Akari enters without hiding her feelings and openly presents herself as someone who loves Tooru.
Karui Hiroshi’s promotional post also teases the possibility that Akari may join forces with the childhood-friend heroine against Aino.
That description points toward Chika, Tooru’s former fiancée and childhood friend, although the exact nature of their cooperation remains part of the new book.
The Shared Home Becomes Even Busier
Tooru and Aino do not live alone. Their domestic life also involves Chika, Asuka, and Ririka.
Chika has known Tooru since childhood and understands parts of his past that Aino did not witness.
Asuka and Ririka are maids, but their relationships with the residents extend beyond routine household work. They regularly participate in the series’ romantic and comedic situations.
Akari’s arrival changes the balance that has developed among them. She must confront Aino’s official position as Tooru’s fiancée while also dealing with the other women already living close to him.
The promotional material describes the competition as becoming more intense, while the series retains its sweet romantic-comedy approach.
Three Store Stories Use Costume Themes
Hifumi Shobo has announced several first-purchase bonuses.
They include:
- Melonbooks: an SS leaflet titled Yukata na Hokuou Bishoujo o Nugasu
- Gamers: an SS booklet titled Mizugi no Hokuou Bishoujo wa Totemo Ecchi
- Toranoana: an illustrated SS card titled Maid na Aino no Himitsu
The author’s promotional post also shows paid extras themed around a yukata, competitive swimsuit, and maid outfit.
Toranoana is selling a limited edition containing an A3 tapestry. It costs 2,145 yen including the regular book, and the tapestry is not sold separately.
Availability is limited and may end before release if allocated stock sells out.
From Web Novel to Manga Adaptation
Karui Hiroshi began publishing the web version through Shousetsuka ni Narou in September 2021.
The story follows Tooru, an isolated high-school student, and Aino, a Finnish heiress regarded as one of the school’s most beautiful students.
After Tooru helps her, the two discover that their families have arranged an engagement. Aino initially wants to escape a political marriage but changes her mind when she learns that Tooru is the selected partner.
The web novel has concluded with 93 episodes. It received the Silver Prize at the 2nd Hifumi Web Novel Award before entering print through Brave Bunko.
A manga adaptation by Takeshi Kagura, using pon’s original character designs, released its first collected volume through Nova Comics on December 25, 2025.
Why This Matters
1) The new rival arrives as a “younger sister”
Akari is not introduced as another ordinary classmate. Her claimed family connection creates a separate mystery around her relationship with Tooru.
2) Aino must defend her established relationship
After several volumes of growing closer to Tooru, she now faces someone willing to express her love without hesitation.
3) Chika may receive another major role
The author’s promotion suggests that the childhood-friend heroine could work alongside Akari in challenging Aino.
4) The store bonuses fit the summer release
Yukata and swimsuit themes match the August publication window, while the maid bonus continues the domestic character dynamic.
Light Novel and Manga Information
The important details currently known are:
- Karui Hiroshi writes Volume 5 and pon provides its illustrations
- Hifumi Shobo publishes it through Brave Bunko
- the Japanese release date is August 25, 2026
- the regular price is 935 yen including tax
- the book contains 240 pages
- its ISBN is 978-4-8240-0737-1
- Aino Lyuty appears on the cover
- Akari arrives and claims to be Tooru’s sister
- she openly confesses her love for him
- Tooru continues living with Aino, Chika, Asuka, and Ririka
- the romantic competition becomes more crowded
- store bonuses are available through Melonbooks, Gamers, and Toranoana
- Toranoana offers an A3 tapestry edition
- the work won a Silver Prize at the 2nd Hifumi Web Novel Award
- its completed web version contains 93 episodes
- Takeshi Kagura draws the manga adaptation
- Nova Comics has published the manga’s first volume
- no official English title has been announced
- Indonesian publication and an anime adaptation have not been announced
- Volume 5 information is available through the official Hifumi Shobo page
- the complete volume list is available through the official series page
- the web novel is available through Shousetsuka ni Narou
- manga information is available through the official Volume 1 page
Closing
Hokuou Bishoujo no Classmate Volume 5 continues Tooru and Aino’s sweet cohabitation while introducing Akari as an aggressive new rival.
The girl claiming to be Tooru’s sister immediately confesses her love and further complicates the household. Volume 5 releases on August 25, 2026, with multiple store bonuses themed around yukata, swimwear, and maid clothing.
- Karui Hiroshi Official X — Volume 5 Cover Reveal, Akari Teaser, and Paid Bonus Themes
- Hifumi Shobo — Official Volume 5 Release Date, Price, ISBN, and Store Bonuses
- Hifumi Shobo — Official Series Volume List and Publication History
- Toranoana — Volume 5 Synopsis and Limited A3 Tapestry Edition
- National Diet Library — Official Bibliographic Data and Page Count
- Shousetsuka ni Narou — Original Web Novel Synopsis and Serialization Information
- Hifumi Shobo — Official Manga Volume 1 Information and Manga Credits
