Kill Blue (Japanese: キルアオ, Hepburn: Kiru Ao) is a Japanese manga series written and illustrated by Tadatoshi Fujimaki. It was serialized in Shueisha's Weekly Shōnen Jump magazine from April 2023 to September 2025, with its chapters collected in thirteen tankōbon volumes. An anime television series adaptation produced by Cue premiered aired from April to June 2026. A second season has been announced.
Contents
Plot
Juzo Ogami is a 39-year-old who works for the Z.O.O. assassin syndicate as their prized hitman. During a job taking out criminals working with the genetic manipulation company Mitsuoka Pharmaceuticals, Ogami is stung by a wasp that modifies his DNA, regressing his age to that of when he was 13. Unable to resume work as a hitman due to his stature, the head of Z.O.O. gives Ogami another assignment while they work on an antidote: attend a middle school the head's daughter is applying to and judge if it is safe. Ogami, due to having no formal education, turns out to love middle school, and must balance his time as a student and an assassin. He must also deal with Noren Mitsuoka, the heiress of Mitsuoka Pharmaceuticals, who may be the key to figuring out how to age Ogami back to normal.
Characters
Juzo Ogami (大狼 十三, Ōgami Jūzō)
Voiced by: Shunsuke Takeuchi (adult), Yūko Sanpei (young) (Japanese); Ray Chase (adult), Caitlyn Elizabeth (young) (English)
A 39-year-old assassin who is aged back to 13 years old after being stung by a mysterious wasp during a mission. Initially not liking the idea of going back to middle school, he soon comes to enjoy it. His skill with a handgun has earned him the nickname "Demon's Left Hand".
Kotatsu Nekota (猫田 コタツ, Nekota Kotatsu)
Voiced by: Shūichirō Umeda (Japanese); Khoi Dao (English)
Ogami's partner. Although not nearly as experienced as Ogami, he is skilled with technology, and has more skill in cooking and house care. He created the pair of glasses that Ogami wears that acts as a camera and radio for him.
Eri Wanibuchi (鰐淵 瑛里, Wanibuchi Eri)
Voiced by: Yumi Uchiyama (Japanese); Dawn M. Bennett (English)
Ogami's ex-wife who is the head of Z.O.O.'s science department.
Noren Mitsuoka (蜜岡 ノレン, Mitsuoka Noren)
Voiced by: Fūka Izumi (Japanese); Kayli Mills (English)
A middle school student and the daughter of Mitsuoka Pharmaceuticals founder. She is constantly hit on by other students, causing her to initially hate men, before befriending Ogami. She helps out her uncle at his ramen shop, and wishes to take it over when he retires.
Chisato Shiraishi (白石 千里, Shiraishi Chisato)
Media
Manga
Written and illustrated by Tadatoshi Fujimaki, Kill Blue was serialized in Shueisha's Weekly Shōnen Jump magazine from April 17, 2023, to September 1, 2025. The series' individual chapters have been collected into thirteen tankōbon volumes, released from September 4, 2023, to December 4, 2025.
Viz Media and Manga Plus simultaneously published the series in English with its Japanese release. Viz Media began releasing the volumes digitally in Summer 2024.
Anime
An anime television series adaptation was announced on September 1, 2025, the same day as the final chapter of the manga. It was produced by Cue and directed by Yasunori Ide, with supervision and series composition handled by Hiro Kaburagi, characters designed by Miho Daidōji, and music composed by Ryo Konishi. The series aired from April 11 to June 27, 2026, on TV Tokyo and its affiliates. The opening theme song is "ATTITUDE" performed by Aespa, while the ending theme song is "KILL SHOT" performed by Riize. Remow licensed the series for simultaneous streaming worldwide on several platforms. An English dub by Bang Zoom! Entertainment premiered on the same day.
Following the airing of the final episode of the first season, a second season was announced.
Reception
The series was ranked seventh in the Nationwide Bookstore Employees' Recommended Comics of 2024 list. The series ranked tenth in the print category at the tenth Next Manga Awards in 2024.
Kaylie Fielden of Screen Rant felt the plot was unique among other hitman manga and praised the beginning chapters. Robbie Pleasant of Multiversity Comics praised the artwork and characters. Regarding the story, Pleasant felt that it had some worrying elements concerning a possible romance between Ogami and Noren but nonetheless handled them well. Kara Dennison of Otaku USA described the series as "Case Closed with added violence".