is a Japanese manga series written and illustrated by Mokumokuren. It began serialization on Kadokawa Shoten's Young Ace Up website in August 2021. As of December 2025, the series' individual chapters have been collected in eight volumes. It follows the story of Yoshiki Tsujinaka, a teenager in rural Japan who discovers that his friend Hikaru Indo has been possessed by an otherworldly entity, forcing him to navigate their changed relationship amid supernatural dangers.
Mokumokuren first conceived of the series while studying for exams and later began posting drawings on Twitter, which led to the Young Ace Up editorial department approaching Mokumokuren to serialize the manga via the Young Ace Up website. An anime television series adaptation produced by CygamesPictures aired from July to September 2025. A second season has been announced.
Upon release of the first volume, the series became a critical and commercial success, with the first volume selling 200,000 copies in three months and receiving critical praise for the story, artwork, and characters.
Yoshiki Tsujinaka and Hikaru Indo are two teenage boys and childhood friends living in a small town in rural Japan. Despite having opposite personalities and different hobbies, the two maintain a close friendship. However, on a winter day, Hikaru is fatally injured while hiking in the mountains alone. Before he dies, a mysterious eldritch being comes across him and consumes him, becoming him physically in the process. This "Hikaru" has all the feelings and memories of the original, yet remains a separate being, something Yoshiki realizes rather quickly. Yoshiki still wants to stay with "Hikaru"; however, his alien nature, along with other eldritch beings and hunters of said beings, may make that impossible.
Mokumokuren first conceived the series while studying for high school entrance exams. After graduating, they began posting drawings on Twitter in their spare time in January 2021. They were later approached by the Young Ace Up editorial department to serialize the manga in Young Ace Up, which they accepted. Mokumokuren is a fan of action manga from Weekly Shà Ânen Jump and Weekly Young Jump, particularly Tokyo Ghoul.
While writing the story, Mokumokuren tried to keep the horror to a minimum by trying to appeal to people's emotions rather than just being scary. They also felt that the theme of the story added to the horror based on the suspension bridge effect, which states that it is easier to fall in love when feeling anxious or fearful. For the artwork, they tried to include onomatopoeia that are not often used, while also having stayed cautious to make sure it worked properly in the context of the story.
Mokumokuren initially introduced The Summer Hikaru Died in 2021 as a boys' love story. They later specified that the manga was never serialized as a boys' love story, instead describing the series as a "coming-of-age horror" with queer themes.
Mokumokuren used their grandmother's hometown as model, where the houses were all packed tightly together and it was normal for the neighbors to come and go without permission. They got the inspiration during their visit to the region. As they wanted the characters to speak in a distinctive dialect, they looked for one that was "slightly different from Kansai dialect" and decided the setting based on place that is located in "mountainous area of Tokai region." As a result, the fictional rural town located between mountains in Mie Prefecture became the setting of the series and some characters are speaking in Mie dialect.
Written and illustrated by Mokumokuren, the series began serialization on Kadokawa Shoten's Young Ace Up website on August 31, 2021. As of December 2025, the series' individual chapters have been collected in eight volumes.
In September 2022, Yen Press announced that they licensed the series for English publication.
A novelization of the manga series, written by Mio Nukaga, was published by Kadokawa Shoten on December 4, 2023. As of July 2025, two volumes have been released. At New York Comic Con 2024, Yen Press announced that they also licensed the novel for English publication.
An anime adaptation was announced on May 24, 2024. It was later revealed to be a television series produced by CygamesPictures and directed by Ryà Âhei Takeshita with him also handling series composition, character designs and chief animation direction handled by Yuichi Takahashi, and "Dorodoro" animation handled by Masanobu Hiraoka. It premiered on July 6, 2025, on Nippon TV and its affiliates. The opening theme song is by Vaundy, while the ending theme song is by Tooboe. Netflix is streaming the series globally, while Abema is streaming it inside Japan for free.
After the airing of the final episode of the first season, a second season was announced.
A stage play adaptation of the manga was announced, and is set to run at Kinokuniya Hall in Tokyo from January 9 to 18, 2026, with Sà Âtarà  Fujii directing and script writing the play while Mikihito Sano is composing the music.
In the 2022 Next Manga Award, The Summer Hikaru Died ranked 11th in the web manga category. It was also the most popular choice among traditional Chinese voters. The series topped the 2023 edition of Takarajimasha's Kono Manga ga Sugoi! list of best manga for male readers. It was also nominated for the 16th Manga Taishà Â. The series ranked fifth in the Nationwide Bookstore Employees' Recommended Comics of 2023. It also ranked seventh in the seventh Tsutaya Comic Award. In 2023, the series was listed by the New York Public Library among its Best Books for Teens that year. It ranked 29th on the 2023 "Book of the Year" list by Da Vinci magazine. In 2024, the first volume and series author Mokumokuren were nominated for the Eisner Award for Best U.S. Edition of International MaterialâÂÂAsia and for Best Writer/Artist, respectively. The series was also nominated at the Japan Society and Anime NYC's first American Manga Awards for Best Continuing Manga Series in 2024; it was nominated in the same category in 2025. The series was nominated for Harvey Awards in the Best Manga category in the same year; it was nominated in the same category in 2025. The series was listed by Yen Press as its top title for 2025.
The first volume received three times more orders than copies available in the first print run. The volume was reprinted six times in three months, having over 200,000 copies in circulation. By October 2022, the series had 550,000 copies in circulation. By June 2023, the series had 1.4 million copies in circulation. By December 2023, the series had 1.9 million copies in circulation. By May 24, 2024, the series had 2.1 million copies in circulation. By June 4, 2024, the series had 2.3 million copies in circulation. By November 4, 2024, the series had 3 million copies in circulation. By July 4, 2025, the series had 3.5 million copies in circulation. By September 26, 2025, the series had 4 million copies in circulation. By December 26, 2025, the series had 4.5 million copies in circulation.
Chanmei from Real Sound praised the story and characters as emotional. Chanmei also praised the artwork, believing it complemented the story well. Tensako Miura from An An praised the story, main characters, and artwork, positively noting the artwork's use of shades of black.