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Under Ninja

Under Ninja (アンダーニンジャ, Andā Ninja) is a Japanese manga series written and illustrated by Kengo Hanazawa. It has been serialized in Kodansha's seinen manga magazine Weekly Young Magazine since July 25, 2018, with sixteen volumes released as of October 2025. The story is set in contemporary Japan, where approximately 200,000 ninjas operate in secrecy, and centers on Kurou Kumogakure, a low-ranking ninja from the organization NIN (National Intelligence of NINJA) who performs international assassinations while posing as an ordinary high school student. The narrative explores themes of hidden identities and covert operations in a modern world, blending action, , and dark humor as Kurou navigates dangerous missions against rival ninja groups like the antagonistic UN (Under Ninja). Hanazawa, known for his previous work I Am a Hero, draws on historical elements such as the Imperial Japanese Army's Nakano School to ground the fantastical premise in a pseudo-realistic framework. As of 2025, the remains ongoing, praised for its intricate world-building and satirical take on ninja lore. Under Ninja has spawned multiple adaptations, expanding its reach beyond the page. A 12-episode television series, produced by and directed by Satoshi Kuwabara, aired on and BS11 from October 6 to December 22, 2023, with streaming available on platforms like and . The faithfully adapts the manga's early arcs, featuring voice acting by talents such as as Kurou, and received mixed reviews for its style and pacing. In 2025, a live-action directed by Yūichi Fukuda premiered on January 24 in , starring as Kurou Kumogakure and as his classmate Ayaka Noguchi. The film, produced by , incorporates high-octane action sequences and a star-studded cast including Shotaro Mamiya and Tsuyoshi Muro, while emphasizing the 's themes of infiltration and inter-ninja conflict; it grossed over ¥1 billion at the within its first month. Blu-ray and DVD releases followed later in the year, further cementing Under Ninja's popularity in both and multimedia formats.

Synopsis and characters

Plot

In modern-day , approximately 200,000 s operate in secrecy, blending into everyday society while engaging in covert operations to address global threats such as . These s are divided between two rival organizations: the government-independent NIN (National Intelligence of NINJA), which conducts assassinations and sabotage, and the opposing UN (Under Ninja), which counters NIN's activities to maintain balance in the shadow world of . The series explores this hidden society, where operatives hold mundane jobs by day but execute high-stakes missions by night. The story centers on Kurou Kumogakure, an unlucky and reclusive high student from the declining Kumogakure clan, who is recruited into the organization after awakening to his latent heritage. As a low-ranking genin operative, Kurou is thrust into the front lines of the conflict, balancing his unremarkable life with intense training and assignments that pit him against the rival UN and foreign threats. His journey highlights the protagonist's growth from an ordinary teenager into a capable navigating the perils of intrigue. The traces its origins to a post-World War II agency established by Allied Command to manage regional security using . The narrative unfolds through episodic missions that showcase Kurou's involvement in and combat against rival groups, while weaving in larger arcs of global ninja warfare and personal skill development. This structure juxtaposes high-tension assassinations and undercover operations—such as infiltrating a high —with Kurou's everyday struggles, emphasizing the tension between normalcy and the secretive demands of ninja life.

Characters

Kurou Kumogakure serves as the of Under Ninja, depicted as a 17-year-old genin-level who begins the story as notably incompetent and plagued by misfortune. His primary motivations revolve around mere survival in the perilous ninja underworld and a desire to prove his worth amid constant setbacks. Over the course of the narrative, Kurou undergoes significant evolution through rigorous training, gradually honing his skills from a novice reliant on luck to a more capable operative. Supporting the protagonist are fellow NIN members, including Kato and , who assist in missions and provide guidance. Rivals from the UN organization occasionally intersect with Kurou's path, leading to conflicts and uneasy alliances. Kurou's high school classmates, such as Ai Kawado, inject into the story through their obliviousness to the ninja world and everyday interactions. Additionally, Kurou's family members from the Kumogakure clan play a role in unveiling his inherited ninja lineage, adding depth to his personal backstory, while NIN officials oversee broader operations. Character dynamics in Under Ninja highlight tensions between novice ninjas like Kurou and seasoned veterans, often manifesting in clashes over strategy and reliability. Subtle interpersonal conflicts and betrayals rooted in organizational loyalties drive much of the plot progression.

Publication and releases

Manga

Under Ninja is a Japanese series written and illustrated by . It began serialization in Kodansha's on July 23, 2018, with the magazine's issue 34, and remains ongoing as of November 2025, having exceeded 120 chapters. The series has been compiled into sixteen volumes, with the first released on February 6, 2019, and the sixteenth published on October 6, 2025. Each volume typically collects eight to ten chapters, along with color illustrations and author afterwords. Key events in the manga's serialization include a three-week announced in the magazine's 18th issue of 2025, during which no new chapters were published, with serialization resuming on April 28. The series was nominated for the 49th in the general category in 2025.

English release

In , the English-language rights to Under Ninja were acquired by Denpa Books, an independent manga publisher specializing in niche titles from . The first volume was released on January 10, 2023, presented in the traditional right-to-left reading format typical of localizations to preserve the original artwork flow. As of November 2025, Denpa Books has published seven volumes in English, with volume 6 released on May 27, 2025, and volume 7 on July 30, 2025, covering the early arcs of the series up to the introduction of key ninja conflicts in . These volumes are available in both print and digital formats, with e-book editions accessible on platforms like and for broader digital distribution. The localization effort emphasizes a faithful of Kengo Hanazawa's original text, maintaining the series' signature and specialized terminology without significant alterations. credits go to Sheldon Drzka, with by Patrick Sutton, and select volumes include cultural footnotes explaining historical or jargon-specific concepts for non-Japanese readers. Internationally, full English editions remain limited outside , with no comprehensive releases across as of 2025 despite interest in select markets like , where a separate edition is handled by . Prior to the official licensing, unofficial fan translations circulated online but were largely discontinued after Denpa's announcement to respect rights.

Adaptations

Anime

The television anime adaptation of Under Ninja was produced by and directed by Satoshi Kuwabara. The series composition was handled by Keiichirō Ōchi, with character designs adapted by . It aired from October 6 to December 22, 2023, for a total of 12 episodes, each approximately 24 minutes in length. The series premiered on and BS11, with additional broadcasts on other networks. The opening theme, "Hyper," was performed by the band Kroi, while the ending theme, "Himitsu," was sung by KOTORI. The adapts the early portions of the ongoing , covering material up to approximately chapter 72 across its 12-episode run and concluding with an original ending to wrap up the season's narrative. To fit the format, it condenses several and introductory from material for improved pacing. Action sequences incorporate () to depict dynamic combat and movements. The voice cast features as the protagonist Kuro Kumogakure, delivering the character's deadpan humor and comedic timing effectively. Following its Japanese broadcast, the series became available for global streaming on , with episodes simulcast weekly during the airing period, and later on in select regions. A was released in Japan on March 21, 2024.

Live-action film

A live-action of Under Ninja was directed and written by Yūichi Fukuda, who is known for his work on action-comedy projects such as The Top Secret: Murder in Mind. The production was handled by Co., Ltd. and Credeus, with emphasizing the manga's blend of and humor in a modern setting. The film stars in the lead role of Kuro Kumogakure, a low-ranking navigating covert operations; as Ayaka Noguchi, the high school girl drawn into the ninja world; and Shinobu Hasegawa in a supporting role as the homeroom teacher. It premiered theatrically in on January 24, 2025, distributed nationwide by . The film condenses the early arcs of Kengo Hanazawa's manga, focusing on Kuro's assignment to infiltrate a high school suspected of harboring a hostile ninja splinter group from the organization UN, opposed to the main body NIN. This adaptation streamlines multiple missions into a cohesive 123-minute narrative, highlighting Kuro's reluctant involvement in high-stakes espionage alongside Noguchi, who becomes an unwitting ally amid escalating threats. Unlike the manga's expansive serialization, the movie prioritizes cinematic pacing, portraying ninja activities through urban chases and school-based intrigue while retaining core characters like the unmotivated protagonist Kuro from the source material. Key promotional events included the world premiere screening on January 8, 2025, at JAPAN HOUSE , followed by a Q&A session with leads Yamazaki and Hamabe. A main trailer was released on October 29, 2024, showcasing the film's action-comedy tone through dynamic fight sequences and humorous ninja mishaps. Distribution began with a wide theatrical release in , achieving over $8.8 million in worldwide earnings. Internationally, the film has been made available for streaming and rental on platforms such as , Amazon Video, and in select regions including , with broader global accessibility expanding post-theatrical run. Blu-ray and DVD releases followed on June 18, 2025.

Reception

Critical response

The manga adaptation of Under Ninja by has been praised for its unique blend of absurd humor and detailed ninja lore, evolving from a slow-paced, peaceful narrative into an action-oriented story that leverages the freedom of to explore character depth and subtle world-building elements like ninja silence techniques. Critics have highlighted Hanazawa's thoughtful approach to on modern , portraying s as covert operatives in contemporary through themes of and cover-ups, such as official excuses for large-scale destructions. This innovation, building on his previous work , earned the series a nomination for the 49th in the general category in 2025, underscoring its recognition for pushing boundaries in seinen storytelling. The adaptation received mixed reviews, with an average score of 6.89 on based on 25,906 user ratings, lauded for its originality in subverting traditional ninja narratives and strong that enhances the comedic elements through fitting, character-driven performances. However, it faced criticism for subpar in early episodes, which detracted from the visual quality, and pacing issues stemming from non-linear storytelling and time jumps that adapted the manga's early arcs too hastily, making the narrative feel confusing for some viewers. Reception for the 2025 live-action film has been generally positive, holding an average rating of 5.6/10 from user reviews, with particular acclaim for the fight choreography's intensity and Kento Yamazaki's standout performance as the lead, delivering precise emotional depth through powerful expressions and vocal delivery. Reviewers noted its faithful yet accessible adaptation of the source material, emphasizing visual spectacle through effective low-budget effects and sound design that build emotional tension, though some pointed to an uneven tone blending fun absurdity with serious action. Across the , , and film, common themes in critical responses include appreciation for subverting tropes by depicting them as flawed, modern spies rather than mythical warriors, which adds fresh absurdity to the genre. Critiques often focus on inconsistent world-building, such as abrupt shifts in the of post-war ninjas that can feel disjointed or hard to follow without prior familiarity.

Commercial performance

The Under Ninja series has seen steady commercial success in , with over 2 million copies in circulation for the first 14 volumes as of 2024. Its nomination for the 49th in the general category in 2025 helped elevate its profile among seinen titles, contributing to sustained interest in the Weekly Young Magazine serialization. The English-language release by Denpa Books has performed modestly in the U.S. market, appealing primarily to fans of Kengo Hanazawa's prior works like . The 2023 anime adaptation, consisting of 12 episodes streamed exclusively on outside , attracted a niche international audience, evidenced by its 4.3/5 user rating from over 5,000 reviews. However, sales, including Blu-ray releases, remained low, consistent with the series' targeted appeal to mature viewers rather than mainstream demographics. The live-action , directed by Yûichi Fukuda and released on January 24, 2025, achieved strong initial results in , with an opening weekend gross of $1,450,725 USD (approximately ¥218 million JPY) and ranking third domestically. It continued to perform solidly, rising to fifth place in subsequent weeks, with a total gross of $8,782,158 USD (approximately ¥1.32 billion JPY) as of March 2025 while surpassing broader market expectations for a manga-based title. International earnings were limited at launch due to a focus on the Japanese market, though premiere events drew notable attendance.

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