Under Ninja is a manga written and illustrated by Kengo Hanazawa of I Am a Hero fame, published by Kodansha in Japan, Denpa in English and by J-pop in Italian. The manga began serialization in Weekly Young Magazine in 2018.
An anime version is animated by Tezuka Productions. It's directed by Satoshi Kuwabara with the script written by Keiichirō Ōchi. It aired in Japan in various TV channels like TBS Television and BS11 from October to December 2023. Crunchyroll streams it in English.
In an alternate world, the Ninja did not disappear even after the end of the Edo period. Their last appearance was in the end of the Pacific War where a group of anti-Imperial Japanese ninjas protected Allied Forces commander Douglas MacArthur from being killed after his arrival in Japan by pro-Imperial ninjas. However, it was reported that the order came from GHQ to disband them. In secret, they still exist. And they're being used by Tokyo for national security policies. Others have either become unemployed, forced to work in menial jobs or are Hikikomoris.
Kurō Kumogakure, who happens to be unemployed, was approached to be a ninja with instructions to investigate Kodan High as his first mission with the National Intelligence of NINJA (or NIN). This turns out to be the influence of another ninja group known as UN, Under Ninja, which NIN quickly comes into conflict with.
Under Ninja contains the following tropes:
- Action Prologue: The manga starts with a raid in a Middle Eastern city by a foreign special forces unit.
- Alternate History: Ninjas were around in Japan until the Pacific War. A group of pro-Allied Forces ninjas saved General MacArthur from being killed.
- Atrocious Alias: Kurō uses the surname "Kumogakure" (Hidden by Clouds) as his surname during his infiltration. Everyone immediately points out just how incredibly conspicuous it is as a name, to which Kurō replies it's one of the top ten most common family names in Japan. No-one believes it.
- Axes at School: With the setting of the first arc being a high school being infiltrated by two ninja factions, this is a given. Batons, spring-loaded knives and later swords all get involved, not to mention the NIN-owned Kill Sat called "Escape" orbiting overhead.
- Brain Transplant: NIN is involved in brain transplanting experiments, including transplanting human minds into cats. This turns out to be in order for NIN's leadership to attempt to live forever, by transplanting their aging brains into new bodies. It's clear the younger ninja in NIN are very uncomfortable with the situation, both ethically and because it will mean they can never reach the top ranks since the leadership never die of old age.
- Breaking the Fourth Wall: In the next episode preview for "Kumogakure Is Within the Top 10 Common Family Names in Japan (Lying)", Eita was challenged to mention his surname. Eita says he can, but finds out that he can't say it. Kumogakure says that he can't do it because the manga (source) has yet to mention it officially.
- Darkest Hour: After Kodan is destroyed by Escape, UN begins to use the stolen NIN data to assassinate NIN agents. This forces the survivors to go and hide. Kato's punished by the higher-ups in NIN for letting Saruta kill Onikobe and get NIN data from Escape stolen. He's later sentenced to die in "Me and Old Dudes" alongside other NIN agents. Kuro's other siblings are forced to take over his work and go after Yamada, partly for killing him.
- Dawson Casting: An In-Universe example: Kurō is supposedly a high school student despite his Perma-Stubble and deep voice making him look almost a decade older. The news bulletin after the Kodan High infiltration goes all to heck reveals he's 24 years old.
- The Dreaded: One of the SOF commandos who found the suicide bomber's body said that he wants to see an actual ninja in action. His commander chides him for saying that and sarcasticaly asks him if he wants to die.
- Elites Are More Glamorous: The manga portrays the ninja as special forces deployed abroad in anti-terrorist missions. It is Truth in Television as recorded documentation in Japan suggests that ninjas were used in pre-Meiji Japan as spies and saboteurs. From the first chapter, the foreign SOF unit in the Middle Eastern city assigned to take out a suicide bomber.
- Gas Leak Cover Up: NIN covers up Escape vaporizing Kodan High School by letting their agents in the government blame the explosion on methane gas buildups.
- Gratuitous Russian: Alexei, being a McNinja from Russia, frequently switches between Russian and (very stilted) Japanese. He is voiced by a native speaker in the anime, which also makes him a case of Eloquent in My Native Tongue.
- Hard-Drinking Party Girl: Ai, who is rarely sober on-screen. Kurō steals her beer on at least one occasion.
- Info Dump: Alexei is given a rather lengthy one by NIN's middle management after several of their agents successfully subdue him, which also serves to give the audience some necessary context that would become As You Know if anyone inside the organization were to talk openly about it. He rather sensibly asks why they bothered giving him all this information if they're going to kill him anyway, and is given the answer that it's because NIN is offering him a job.
- Invisibility Cloak: NIN researchers were able to make optical camouflage for its ninja agents. To make it effective (and work), the user must chant a mantra in order to activate it. UN also has access to the same tech too.
- Middle Eastern Terrorists: The suicide bomber found in a safehouse was about to use his suicide vest when a ninja killed him.
- Myth Arc: The first part/s of the manga has NIN investigate Kodan High School and why UN is interested in it. NIN finds out that UN is launching an attack on KHS as a distraction so that they can get to NIN's Kill Sat known as Escape, breach it and get their hands on confidential NIN data. This was followed by assassinating most of their rank and file by miniature FPV drones that survivors are forced to hide and restrict their activities.
- Mutual Kill: Saruta uses a combat knife to attack Onikobe. While she was able to lower her combat visor on her shinobi shozoku to minimize the damage, Saruta fires the knife's blade to her head. Before she dies, she stabs Saruta in the chest. He later dies when Escape opens fire on KHS.
- Off with His Head!:
- At the start of the manga, a foreign special forces unit in the Middle East finds the corpse of a suicide bomber with no head and thumb, which was done to avoid triggering the remote detonator attached to his suicide vest.
- At the end of the Kodan High School battle between NIN and UN, Kurō is seemingly killed and decapitated by the main UN agent. Eita later ends up kicking the head off the side of the building in shock.
- Title Drop: Under Ninja's the name of a supposed black ops ninja unit with ties to the Ministry of Health, Labor and Welfare. It started out from the remnants of the Nakano School after Japan was defeated in WWII.
- Two Lines, No Waiting: The manga starts with two plots. One consists of Kurō being recruited as a ninja to investigate what's happening at Kodan High. Meanwhile, Alexei has come to Japan from abroad in order to start infiltrating a ninja clan so that he can see his daughter again.
