It’s impossible to talk about Under Ninja without mentioning director Yuichi Fukuda. He became well-known for the live-action Gintama and Brave Yoshihiko series, building a big following thanks to his unique sense of humor.
This style is clearly evident in this film as well. After watching the trailer, I hoped Fukuda would hold back on his usual comedy and focus more on the original’s serious tone. While the action and art direction are solid, and the film presents a cinematic experience characteristic of Fukuda, the comedic approach ultimately influences the storytelling in distinct ways.
Yet, after seeing the full movie, I found that Fukuda’s gag scenes continued to disrupt the story’s flow, echoing the earlier challenge of balancing comedy and seriousness.
About the Original Work
The film ‘Under Ninja’ is based on the manga series by Kengo Hanazawa. Serialization began in Kodansha’s ‘Young Magazine’ in 2018 and continues as of January 2025, making it a popular ongoing series.
Kenji Hanazawa is a manga artist and the original creator of the film ‘I Am a Hero’. ‘I Am a Hero’ serialized from 2009 to 2017, gaining overwhelming popularity as a zombie panic story. In 2015, it was adapted into a live-action film directed by Shinsuke Sato. Despite its bold R18 rating, it achieved significant box office success.
“Under Ninja” garnered attention as Kengo Hanazawa’s new work following the conclusion of “I Am a Hero”. It features a novel premise where approximately 200,000 ninjas are secretly active in modern Japan, blending serious action with black humor. The original manga contains adult-oriented content, including quite grotesque depictions and violent imagery, that unfolds Hanazawa’s signature dark worldview.
In 2023, it was adapted into a TV anime (12 episodes total), which was praised for its relatively faithful recreation of the original work’s unique atmosphere. Following the anime, this live-action adaptation is part of the ongoing media mix expansion. However, the choice of director Yūichi Fukuda led the film in a notably different direction from both the original manga and anime, resulting in contrasts discussed earlier.
A common thread in Kengo Hanazawa’s works is the sharp depiction of humanity’s fundamental weaknesses and societal contradictions within seemingly comical settings. ‘Under Ninja’ is no exception, using the extraordinary existence of ninjas to highlight the distortions of modern society and the complexity of human relationships. However, the film version struggles to fully convey the depth of the original work.
The Brilliance of the Action Scenes
The best part of ‘Under Ninja’ is definitely its well-executed action scenes. Building on Fukuda’s previous collaborations, action director Kageya Tabuchi truly showcases his strengths here.
Particularly memorable was the sword-fighting sequence near the end. The action sequence where Kuro, played by Kento Yamazaki, and the other ninja members confront their enemies, wielding Japanese swords, was directed with such realism that everything came through vividly: the clang of blades clashing, the trajectories of the blades, and even the actors’ breathing.
This is classic Kageya Tabuchi. The action balances spectacle and realism, capturing how ninjas might move.
The Cast’s Efforts and Directing Challenges (Particularly the Handling of Minami Hamabe)
In terms of casting, this film was blessed with talented actors.
Kento Yamazaki’s relaxed performance stands out from his intense roles in ‘Kingdom’ and ‘Alice in Borderland’.
Minami Hamabe, a talented young actress with proven experience in ‘Shin Kamen Rider’ and many dramas, is limited to a comic relief role in this film.
The main issue is that Minami Hamabe’s appearance makes her unconvincing as a high school student, which breaks immersion. Although her acting is not the problem, this miscasting disrupts audience engagement and raises questions about the director’s choices.
Particularly problematic was the so-called “booger scene.” There’s a long take where Kuro tells her, “You’ve got boogers on your face,” and Minami Hamabe’s character repeatedly slaps her own face. This felt incredibly drawn out.
Sound effects like “pai pai pai” are added, and Kento Yamazaki keeps repeating “Not yet.”
I couldn’t see the point of this scene. Worse, it was repeated—and the second time dragged on, even showing Hamabe stifling laughter.
Having a talented actress make silly faces for laughs might be something Director Fukuda is known for, linking back to his signature comedic approach. But does that really show off what an actor can do?
The film does not fully utilize Minami Hamabe’s talents, limiting the range of her performance.
I never understood her character. She tells Kuro, “You’re in the way,” but later seems to like him. When she faints, she makes wrestler faces, and when she looks at Kuro asleep, she rolls her eyes. I couldn’t tell what the director intended.
Gag scenes fragment the narrative. The pros and cons of in-jokes
The biggest issue with ‘Under Ninja’ is that the gag scenes consistently break up the story’s flow, reinforcing the earlier point about tonal imbalance.
In director Fukuda’s works, “ad-lib style acting” is often seen.
Actors ad-lib, making co-stars laugh. This might have felt new in ‘Yoshihiko the Brave’, but in this movie, it feels out of place.
Another issue is that the film relies on inside jokes without setup.
Take, for example, the opening scene with Jiro Sato. He plays a struggling novelist whose entire manuscript gets rejected by his editor, played by Mai Shiraishi, who tells him, “Please rewrite everything.” Sato then repeats, “What?” “What?” “What?” over and over. I couldn’t understand why this scene was supposed to be funny.
There’s no context about his manuscript or feelings, so it just reads as Sato Jiro being odd. If it’s funny, it’s likely only to those who know Sato Jiro.
For people who’ve seen many of Director Fukuda’s works, or who find this kind of performance by Sato Jiro “typical Fukuda” and enjoy it, this might be funny.
But for someone seeing a Fukuda film for the first time, or for fans of the original ‘Under Ninja’ manga, it’s worth considering whether this comedic direction is effective, especially given the tonal contrasts noted earlier.
The Confusion of the School Part Where the Core of the Story Isn’t Visible
The most confusing thing about ‘Under Ninja’ was its unclear plot development, especially when abrupt shifts left me unable to understand character motivations or the overall story direction.
In the early setup, Kuro’s mission is presented: infiltrate the school and find the Under Ninja. At this point, I was really excited.
I expected some exciting scenes, like Kuro doing ninja activities in secret while tracking down his target inside the school.
But Kuro doesn’t hide. He uses an invisibility trick in class, steps into bullying incidents, and gets filmed by students while climbing school walls.
The contradiction of a ninja not hiding from the public undermines the story’s logic, and because the film does not address this, it creates confusion about the character’s actions.
I got even more confused when the killings started at the school. Who was attacking whom? Why? What was the goal? The film never explains any of this during the action scenes.
Maybe the frequent gag scenes had already worn me out, making it hard to follow the story. Or maybe the script itself was confusing. Either way, watching the film while constantly thinking, “I have no idea what’s happening,” became really stressful, echoing earlier frustrations.
The Appeal of Creepy Nuts’ Theme Song and the Film’s Music
Creepy Nuts wrote the theme song “Doppelgänger” just for this film. It plays during the end credits and matches up with scenes from the movie. For example, when the lyrics mention a “round-trip slap,” you see Minami Hamabe flapping her hands and slapping her own face.
Honestly, I don’t know whether Creepy Nuts wrote the lyrics after watching the film, or whether the song came first and the scenes were made to fit. Either way, “Doppelgänger” is a fantastic track that sticks with you after the credits.
Summary: A Work Where Talented Actors and Staff Go Unrewarded
Overall, the comedic elements in ‘Under Ninja’ are unlikely to appeal to all viewers.
Keiya Tabuchi’s action direction was excellent, and the cast, especially Kento Yamazaki, gave great performances. Kengo Hanazawa’s original worldview should have worked well on screen, and Creepy Nuts’ theme song and soundtrack added a lot to the film.
However, I feel director Yuichi Fukuda’s signature comedic direction ruined all of this. The in-joke gags and overly long ad-lib scenes disrupted the narrative flow, leaving the audience behind.
Of course, some people might have enjoyed this film. Fans of Director Fukuda may like his style. But for fans of the original manga or those looking for a strong movie experience, this film was a letdown.
