Miharu Rokujou

The apathetic 14-year old protagonist of the series. Although Nabari's most powerful secret art, the Shinrabanshou (lit. All Things in Nature), is literally written into his body and he is venerated by all of Nabari's ninja as king, Miharu cares little about his gift's profound merits. His only goal is to inherit the family's okonomiyaki store.

• Anti-Hero: Type I.
• Back from the Dead
• Blessed with Suck
• Cute Shotaro Boy
• Cross-Dressing Voices
• Dangerous Forbidden Technique: The Shinrabanshou.
• Deliberately Cute Child
• Dynamic Character: In later chapters, lots of characters remark on how much more open and "alive" he's become.
• Emotionless Boy
• Friendless Background
• Green Eyes
• I Just Want to Be Normal
• Lack of Empathy: One of his defining traits at the beginning of the manga.
• Picky Eater: Miharu lives on a diet of mostly sweets and liquids, which would explain why he weighs all of 77 pounds.
• Rie Kugimiya: Miharu's voice in the anime. Not kidding.
• Saved by Canon: Sort of.
• Scars Are Forever: The scar Miharu gets on his hand from stopping Yoite from killing Yae Oda is brought up again at the very end of the manga.
• The Stoic: Once Yoite is in the picture, though...
• Strong Family Resemblance: Looks nearly identical to his mother, Asahi.
• Used to Be a Sweet Kid
• Zettai Ryouiki: Manages this with shorts.

Kouichi Aizawa

One of Miharu's classmates, Aizawa is the leader of the school's Nindou club. He's actually an owl with a human heart who was made immortal by a previous hijutsu user. He and Shijima both want Miharu to free them from the "curse" of immortality.

• Badass Bookworm: Aizawa Kouichi seems like a mild-mannered and well-spoken young man often taken aback by his friends' quirks and isn't the best at ninja techniques...except when push comes to shove, he becomes a cool, level-headed, and actually professional ninja who doesn't hesitate to kill, brainwash, and do whatever it takes to free himself from the curse of immortality, even if it means siding with the enemy village.
• Bishōnen
• Blessed with Suck
• Fan Nickname: Owlzawa, Oldzawa, and Shotazawa for Kouichi's various forms.
• Hellish Pupils: At times. Presumably because he's not completely human.
• I Just Want to Be Normal
• Immortality
• Megane
• Older than They Look/Really 700 Years Old
• Red Eyes, Take Warning: While he apparently isn't evil, he's certainly more ruthless than he first appears, and he's definitely planning something behind his team's back. Plus, he's immortal, and not exactly human.
• Relationship Voice Actor: Miharu is Shana while Kouichi is Yuuji.
• Satoshi Hino
• Scary Shiny Glasses
• White-Haired Pretty Boy
• Who Wants to Live Forever?

Tobari Durandal Kumohira

Miharu and Kouichi's 25-year-old teacher in the front world. Born in Ireland, he was forced by his grandfather to go to Japan and learn to become a ninja. Among the Banten ninja, Thobari is the most vehement dissident against Miharu using the Shinrabanshou, instead advocating its permanent seal.

• Afraid of Needles: Thobari's irrational fear of vehicles of all sorts. Apparently he used to be an award-winning choirboy in Ireland, but being forcibly brought over to Japan in an airplane traumatized him so much he became tone deaf.
• But Not Too Foreign: Partially Irish.
• Failure Knight: His devotion to Miharu is partially because of his guilt from failing to seal the Shinrabanshou 10 years ago.
• Fan Nickname: Pedo-sensei.
• My Greatest Failure
• Phenotype Stereotype: Averted: Kumohira is partly Irish, and he does have blue eyes, but with dark hair instead of blond.
• Oireland: Averted: Kumohira averts almost all of the typical Oirish stereotypes, including drinking.

Raimei Shimizu

The female lead of the series. She is a samurai of the Shimizu clan and has sworn to kill her older brother Raikou, who annihilated the clan 5 years ago.

• Action Girl
• Break the Cutie
• Determinator
• Hair Decorations
• Hot Blooded
• Genki Girl: She does have angsty moments, though.
• Girlish Pigtails
• Honor Before Reason
• Hot Blooded
• New Transfer Student: Raimei's case is a little strange in that she just sort of...invades. The other students seem to love her, though.
• Plucky Girl
• Roaring Rampage of Revenge
• Running Gag: Her tendency to mistake people for each other when she's excited about something.
• Samurai

Kotarou Fuuma/Inasa

The leader of Fuuma Village. He loves women as he claims that if he had the power of the Shinrabanshou, he would turn the Fuuma Village into a paradise where all the world's women are in love with him.

• Big Bad
• Double Agent
• Evil All Along
• For Science!
• Four Eyes, Zero Soul
• Handsome Lech
• Historical Domain Character: Loosely based off of the real-life Fuuma Kotaro.
• Immortality
• Large Ham
• The Man Behind the Man
• Manipulative Bastard: It turns out that Fuuma's been tricking, playing with and manipulating everyone from the very beginning.
• Scary Shiny Glasses
• Stalker with a Crush: He desires the Shinrabanshou because he wants to possess its female spirit, whom he affectionately calls "lovely Shinra".
• Voluntary Shapeshifting
• Would Hurt a Child

Saraba

Fuuma Kotarou's second-in-command.

• Cool Big Sis: To Raimei and Juuji.
• No Name Given: Her full name is never given.

Juuji Minami

A 12-year-old medical ninja.

• The Medic
• Token Mini-Moe
• You Gotta Have Blue Hair

Tojuro Hattori

The leader of the Iga clan and the Kairoushuu. His ideal is to change history and achieve equality among humans with the Shinrabanshou. Hattori takes in many outcasts, offering them a place in the Kairoushuu. Despite this kindness, though, Hattori has little qualms about eliminating those who oppose him.

• Dark Messiah
• The Heavy: Hattori appears to drive most of the plot, though he isn't actually the Big Bad — Fuuma is.
• Historical Domain Character: Hattori Hanzou, who, unsurprisingly, was the rival of the real-life Fuuma Kotarou.
• Unwitting Pawn
• Utopia Justifies the Means
• Visionary Villain
• Well-Intentioned Extremist

Ichiki

Often seen in the company of Hattori, Ichiki is the leader of Kasa. Ichiki is always seen dressed in a traditional kimono and appears to be blind.

• Bob Haircut
• Chekhov's Gunman
• Dragon with an Agenda
• Eyes Always Shut: Justified in that she's blind. She opens them after killing Hattori, though.
• Karma Houdini
• No Name Given: Her full name is never given.
• Older than They Look: She's supposedly 49.
• Yamato Nadeshiko

Yoite

A 16-year-old ninja who uses the Iga's kinjutsushō "Kira", a technique that shoots the user's ki into the target's body and controls it from the inside out, causing the target's bones to break or their body to completely explode. The cost of using this technique is the loss of the user's life force. When Yoite is introduced, he has only a few more months to live.

According to Word Of God, Yoite and Miharu are the series' two protagonists despite Yoite's absence after his death.

• Abusive Parents
• Anti-Hero
• Ambiguous Gender: Subverted. the reader (and even most characters, apparently) start out believing that Yoite is a boy. Later it turns out that he's actually... intersexual. It doesn't really matter in the long run, though, and isn't gone into in much detail, only the readers now know another reason for his angst and identity issues.
• Badass Longcoat: Yoite is almost never seen without some sort of thick, black coat. He won't take it off, even if it's the middle of summer or if he's soaking wet.
• Big Eater: Yoite can be seen eating huge amounts of food in the background of various scenes. He'll eat just about anything since his Kira skill is robbing him of all his senses, and has already taken his sense of taste.
• Berserk Button: Being called an Emo Kid, in the dub.
• Blessed with Suck
• Cast From Lifespan: The Kira technique is powered by Yoite's Life Energy.
• Cross-Dressing Voices
• Dangerous Forbidden Technique: Kira.
• Enigmatic Minion
• Go Out with a Smile
• Handicapped Badass: Regularly faints, always coughing his lungs out, can barely hear and see by chapter 50. Not that his opponents can tell.
• Hates Being Touched: Though he ends up allowing it of Miharu sometimes, "'Don't touch me" is easily the phrase he says the most.
• Hermaphrodite
• I Just Want to Be Normal
• Incurable Cough of Death: One symptom of Yoite's condition.
• Nice Hat: Yoite's giant cap. Some fans have called this series "The Hat Anime." He loses it surprisingly often for something so iconic, though.
• Only One Name
• The Quiet One
• The Runaway
• Scars Are Forever

Kazuhiko Yukimi

A 27-year-old ninja. He acts as a squad leader on field missions and is a freelance writer in the front world. He claims to hate kids and calls them "brats".

• Abusive Parents
• Adult Child: Definitely.
  Yukimi: HOW ABOUT I JUST DYE YOUR HAIR *** COLORED WITH ***, HUH?! RETARD-!!
  Thobari: Are you an elementary school student?
• An Arm and a Leg
• Boring, but Practical: Yukimi doesn't do very many fancy ninja techniques or amazing physical feats. He does, however, have a gun.
• Child Hater: Self-claimed. It doesn't stop him from being a Papa Wolf, though.
• Good All Along
• Handicapped Bad Ass
• Jerk with a Heart of Gold
• Kindhearted Cat Lover
• Parental Substitute: To Yoite. Later to Miharu too.
• Papa Wolf: Yukimi betrays Kairoushuu, his home and family since he was a teenager, and loses an arm in order to protect Yoite. He also becomes surprisingly protective of Miharu, even before promising Yoite to watch out for him.
• Punch Clock Villain: Before his Heel Face Turn.
• Red Herring Shirt: Looks like a typical Mook in his first appearance.

Kazuho Amatatsu

Yukimi's younger sister and Yoite's personal physician. Despite her medical license, she currently works at a sushi restaurant.

• The Medic

Raikou Shimizu

A 20-year-old samurai of the Shimizu clan. When he was fifteen, he single-handedly massacred his entire clan, with the exception of his sister Raimei. This action was actually vengeance against his uncle and his gang, who murdered his parents in a coup d'état to take over the clan.

• Aloof Big Brother
• Ambiguously Gay
• Anti-Hero: Type IV.
• Badass Long Hair
• Berserk Button: When anyone (besides him) hurts Gau.
• Bishōnen: To the point that a lot of non-fans probably think he's a woman.
  • Long-Haired Pretty Boy
• Comedic Sociopathy: His abusive treatment of Gau would actually qualify as domestic violence if Gau actually minded it.
• Dead Best Friend
• Defiant to the End: In the manga. Luckily, he doesn't die from it.
• Determinator
• The Dragon: Was Hattori's right-hand man at one point.
• Drives Like Crazy
• Every Boy Is Cuter With Hair Decs
• Failure Knight: His decision to save Gau despite his being from the surface world stems from the regret he felt from not saving his best friend five years ago.
• Heroic Self-Deprecation: Raikou is convinced that Gau won't wake up from his coma because he doesn't want to see his face. Which might be justified if it was anyone else, but it's Gau we're talking about here...
• Heterosexual Life Partners: With Gau...Though Your Mileage May Vary about the "heterosexual" part...
• Honor Before Reason
• Memetic Outfit: His infamous "USA-CHAN" outfit◊. It's amazingly well-known for something he was only shown wearing for a single panel in the manga.
• One-Hour Work Week: He apparently has a job making paper in the "front" world.
• Must Make Amends: After accidentally causing Gau to fall into a coma, Raikou does everything in his power to find a way to save him, including reading tons of medical books and going to Alya Academy in hopes of using Daya on Gau.
• Pay Evil unto Evil: Murders people on a regular basis for misusing ninjutsu for crimes like stealing.
• Samurai
• Rummage Sale Reject: Just look at any outfit he's ever worn in the course of the series. Seriously, any of them.

Gau Meguro

Raikou's extemely devoted partner. He assists Raikou with his responsibilities to the Kairoushuu, usually compiling reports and taking samples from their targets.

• Adorkable
• Butt Monkey: Often on the receiving end of Raikou's physical abuse.
• Distressed Dude
• Fan Boy: Of Raikou.
  • Hero Worshipper
• Heterosexual Life Partners: With Raikou.
• Hot Blooded: Gau's default mode◊.
• Hypercompetent Sidekick: To Raikou. Despite being a very talented swordsman, Raikou isn't very competent in the more real-world life skills, particularly admin work, which is where Gau dutifully and diligently picks up the slack.
• Keet
• Morality Pet: To Raikou.
• Nonaction Guy
• Pay Evil unto Evil
• Tender Tears: Cries when he meets Raikou for the first time, when Raikou tells him about his past, when he gets slashed by Raikou, when he intervenes in Raikou and Yukimi's fight, when he calls Yukimi on the cellphone, when Raikou gets stabbed, etc, etc...
• Tsurime Eyes
• Undying Loyalty
• Wide-Eyed Idealist
• Yes Man: Gau is described as being "Raikou's little yes-man". So much so, that Kazuho and Yukimi are both taken-aback when Gau absentmindedly expresses doubt in front of Raikou on his course of action.

Shijima Kurookano/ Shiratama

A mysterious member of the Alya Academy Student Council who seems to know more than she lets on. She's actually a cat with a human heart who was made immortal by a previous hijutsu user. She and Kouichi both want Miharu to free them from the "curse" of immortality.

• Cats are Mean: She's notably more ruthless than Kouichi, an owl, is.
• Cool Pet
• Cute Bruiser
• Eyes of Gold
• Hellish Pupils: At times. Presumably because she's not completely human.
• I Just Want to Be Normal
• Immortality
• Older than They Look/Really 700 Years Old
• Pint Sized Powerhouse: Despite being the smallest character in the series, she's a skilled fighter and even manages to take down Raikou after fighting for an entire night.
• Token Mini-Moe: Ironically one of the oldest characters in the series.
• Wild Card
• Who Wants to Live Forever?
• White-Haired Pretty Girl
• Wolverine Claws

Shinrabanshou

• Deity of Human Origin: She was the first user of the Shinrabanshou.
• Rapunzel Hair
• Reality Warper
• Sealed Evil in a Can

Hanabusa Seki

Thobari's girlfriend. She's completely uninvolved with the world of Nabari and treats everyone (including enemy ninjas) kindly, much to Thobari's horror.

• Older than They Look: She's 40.
• Team Mom

Yae Oda

• Mama Bear: Sought revenge for her daughter.
• Seers