Is Under Ninja Worth Reading? Review & Where to Read
Quick Answer
Yes, if you liked the bleak, observational edge of I Am a Hero and want it applied to secret-ninja conspiracy instead of zombies — Under Ninja is funnier and more unsettling than its premise suggests.
Quick Verdict
“It plays modern ninjas for deadpan comedy about failure and unemployment right up until it suddenly doesn't, and that whiplash is the whole point.”
Best for: Readers who want dark, satirical seinen that can turn from absurd comedy to genuine brutality without warning.
Not for: Readers who want tonal consistency, or who'd rather not track a large, fast-introduced cast of rival ninja factions.
- Type
- Manga
- Genres
- Action, Comedy
- Status
- Ongoing
- This review
- Minor Spoilers
- Author
- Kengo Hanazawa
- Publisher
- Denpa
- Platform
- Denpa
| Quick facts | |
|---|---|
| Format | Manga (seinen), 18 volumes |
| Run | 2018–present · ongoing |
| Community score | AniList 6.8 · MangaUpdates 7.0 |
| Content | Graphic violence, mass-casualty content |
| Where to read | Denpa — official |
Overview
Kuro Kumogakure is unemployed, aimless, and in his mid-twenties, which makes him a strange choice to infiltrate a high school undercover — except that in the world of Under Ninja, modern ninjas are a real, secretive profession, and the unglamorous ones like Kuro take whatever infiltration jobs they can get. His mission to investigate a rival ninja organization operating out of the school pulls him into a conspiracy involving government cover-ups, immortality experiments, and a splinter group willing to kill en masse to get what it wants.
What it does well
Kengo Hanazawa (I Am a Hero) brings the same bleak, observational humor to Under Ninja that made his earlier work stand out — this is a story about ninjas, but it's just as interested in unemployment, aimlessness, and the gap between how impressive a 'secret ninja world' sounds and how shabby it actually is for the people stuck at the bottom of it. Kuro passing as a teenager at 24 is played for very dark comedy rather than played straight, and that satirical edge keeps the story from just being another secret-organization action series.
When it does turn toward action and conspiracy, it commits hard — the plot escalates into genuinely startling, brutal territory (government cover-ups, brain-transplant immortality experiments, a strike team willing to kill en masse), and Hanazawa draws violence with the same unflinching, visceral clarity that defined his earlier work. The tonal whiplash between absurd comedy and sudden brutality is deliberate, and it's effective at keeping the story unpredictable.
Where it falls short
That tonal whiplash won't work for everyone — the shift from deadpan comedy about an unemployed loser faking his way through high school to sudden, graphic mass-casualty violence can feel jarring rather than purposeful if you're not already on the story's wavelength. The large cast of ninja factions and rival organizations also gets introduced quickly, and keeping track of who's allied with whom takes real attention.
Verdict
Under Ninja is a dark, funny, frequently brutal take on the secret-ninja-organization premise from a creator who's clearly more interested in what that premise says about ambition, failure, and institutional rot than in straightforward spy-action thrills. If you liked the bleak comedy of I Am a Hero and want something in a very different genre with a similar sensibility, this delivers — just be ready for the violence to turn serious fast.
Strengths & Weaknesses
Strengths
- Kengo Hanazawa's deadpan, observational comedy about unemployment and failure gives this a sharper edge than a typical ninja-action series — Kuro's whole situation is a joke about how unglamorous the 'secret ninja world' actually is for its bottom rung.
- The violence, when it arrives, is drawn with the same unflinching clarity that made Hanazawa's earlier work (I Am a Hero) distinctive — it's genuinely startling rather than cartoonish.
- The central conspiracy escalates into real, high-stakes territory (government cover-ups, immortality experiments) without losing the series' satirical sensibility.
- The fourth-wall-aware, absurdist touches keep the tone unpredictable in a way that's rare for the genre.
Weaknesses
- The shift from absurdist comedy to sudden graphic violence is deliberate but can feel jarring if you're not already attuned to Hanazawa's tonal whiplash.
- A large cast of rival ninja factions gets introduced quickly, and tracking who's aligned with whom takes real effort.
- The bleak, cynical worldview underlying the comedy won't appeal to readers who want their action series to stay lighter.
Similar Titles
Same creator, same observational bleakness applied to a completely different genre (zombie horror instead of ninja conspiracy).
Shares the willingness to pair absurd comedy with sudden, graphic violence in a seinen action framework.
Golden Kamuy
Different tone and setting, but similar mix of dark humor and brutal violence in service of a larger conspiracy plot.
Where to Read Officially
| Platform | Format | Pricing | Region notes | Link |
|---|---|---|---|---|
| Denpa | Print & digital volumes | Paid | Region availability varies | Open |
Prefer to watch? There's an anime
UNDER NINJA: see where to stream it legally, plus episode guides and trailers, on Watchanimee.
Frequently Asked Questions
Is Under Ninja by the same creator as I Am a Hero?
Yes — Kengo Hanazawa writes and illustrates both, and they share a similar bleak, observational sensibility despite being in different genres.
How violent is Under Ninja?
Very, once the plot escalates — expect graphic, sudden violence including mass-casualty scenarios, played straight rather than for comedy.
Is there an anime?
Yes, Under Ninja has an anime adaptation.
How many volumes are out in English?
Denpa has released multiple volumes in English, with the Japanese series still ongoing.
