In contrast to its sister manga, Triage X is mainly made up with Action Girls and aside from the male protagonist, nameless males last only a few chapters.
Please note that if you're watching the anime and you haven't read the manga yet, be careful of spoilers along the way, especially regarding those under "The Mastermind", which are unmarked.
Arashi Mikami
A member of Black Label and the main male protagonist of the series.
Arashi is a handsome but socially awkward high school student that belongs to a vigilante group that deals with criminals the police are unable to. During missions, he is usually partnered up with Mikoto and together they make a fearsome duo.
When he was just a small boy he was severely scarred during a terrorist attack that took the life of his best friend, Ryu Mochizuki. Masamune Mochizuki saved his life by transplanting the organs of his own son into Arashi, an act that has made Arashi incredibly loyal to the Black Label Organization.
- Badass Biker: Arashi when he rides on Mikoto's bike.
- Belligerent Sexual Tension: So much with Mikoto that it's painful to watch at times.
- Captain Ersatz: It can be this and an Expy for Sousuke Sagara. Both of them lost their parents at a young age and are having a hard time expressing themselves when they're not shooting bad guys.
- Dark and Troubled Past: When Mikoto gets fed up with Arashi questioning the orders of their boss, she goes over to his stall in the bathroom and gazes upon his cut and paste body, something that horrifies her. We find out that when Arashi was a small boy playing with his best friend Ryu, there was a terrorist attack that caused Arashi to shield his best friend in the damage. Though he succeeded in protecting Ryu's physical body, his mental state was long gone. Ryu's father (The Chairman of Black Label) declared his son dead and used the organs from his body to transplant them into Arashi and save his life. This explains why Arashi is always questioning whether it's really him making the decisions or his deceased best friend.
- Fan Disservice: Though he does have an impressive physique, the scars all over his body are a bit off putting.
- Freudian Excuse: He tries to give the first criminal he assassinates a chance of Redemption Equals Death, by shooting themselves with a gun. The reasoning he uses is so they can die as a human instead of being slaughtered like the monster they are. Instead, the guy fires his single bullet at Arashi, with deflects off his helmet.
- Good Scars, Evil Scars: He is scarred from the terrorist bombing that killed Ryu.
- I Call It "Vera": The long-barreled Hardballer known as "Long Slide", the V10 known as "Knuckle", and the sawed-off shotgun as "Double Joker".
- Innocently Insensitive: Arashi comes off as this several times to his friends, not because he's purposely trying to hurt their feelings but because he simply doesn't understand the word "tact" and knowing when stating his blunt opinion will only make things worse.
- I Owe You My Life: Because the Chairman transplanted his own son's organs into Arashi (and thus saving his life), Arashi joined the organization to repay his debt and will never consider the thought of betraying the Chairman.
- Mr. Fanservice: The author doesn't hold back any shots of Arashi being topless almost every chapter. Despite his body's unfortunate scars, he's still a chiseled, handsome young man.
- The Stoic: Aside from an occasional smirk and intense snarl every now and then, Arashi will always have a blank look on his face as if he simply doesn't give a crap about what goes on.
- Ship Tease:
- Arashi gets some pretty interesting moments with Mikoto who obviously has feelings for him. Not only her, but his classmate Kominato gets some as well.
- And later, Arashi and Hitsugi are shown to have some history together as well. She even french kisses him.
- Sleep Cute: After visiting Mikoto in the hospital after she was injured, Arashi falls asleep on her bed. You can't deny he looks cute when he sleeps.
- Sole Survivor: Only surviving member of his own family to survive a bombing attack. From Volume 13, it's suggested that D's his father and he went nuts from being seriously injured.
- Survivor Guilt: Feels this way after failing to save his friend from a bomb blast. Despite trying to shield him with his body, Ryuu suffers a concussion from the blast, and is declared brain-dead. Arashi then receives organs and limbs from his dead friend.
- Undying Loyalty: Towards the Chairman and by extension, towards Black Label.
- When He Smiles: For someone who never expresses any emotion than the constant blank stare on his face, the smirk he can produce when he is happy is heart warming (just look at his profile picture).
- Would Hit a Girl: Arashi doesn't hesitate to fight females if they're known to be hostiles. Just ask Lady Dire...
Mikoto Kiba
Another member of Black Label and the main female protagonist.
She is usually partnered up with Arashi and as such is one of his closest friends. At school, she is his senior and acts calm and sophisticated like a proper lady. However, this is just a farce as during her missions her true colors are revealed and she is a short-tempered, foul-mouthed renegade that doesn't hesitate to cut loose when the opportunity presents itself.
She belonged to the Yakuza Kiba family, and her older brother Yuki tried to change it from the inside, which led him being killed on an arranged motorcycle accident. Mikoto was also critically injured in said accident and was only able to make it through alive thanks to the Mochizuki Hospital Staff. This act eventually led to her joining the Black Label Organization.
- Action Girl: Is probably the poster child for this manga.
- Ambiguously Bi: She has feelings for Arashi, but several women around her (namely Sayo and Chikage) don't believe she's straight, hence why they frequently tease her. For her part, Mikoto very much notices but typically doesn't put up much resistance despite clearly being flustered and not knowing what to do. Unlike Chikage, it's unclear to the audience and to Mikoto herself whether she's canonically bi or not.
- Badass Biker: Even back in her younger days.
- Berserk Button: Quite a numerous list (in the manga anyway) but one of the most prominent examples is telling her to forget about her brother. Arashi learned this the hard way.
- Big Brother Worship: When she was younger she always wanted to go where her older brother went and didn't want to do anything with anyone else. She idolized her brother because of his courage and his fearlessness and aspired to become like him, which led to her learning how to ride a motorcycle.
- Clingy Jealous Girl:
- Not as much as you'd expect but this definitely pops up every now and then whenever she sees Arashi interacting with other girls, usually Kominato.
- It's exaggerated when she witnesses Hitsugi and Arashi making out. Before she can interogate Arashi on what happened, Hitsugi grabs him and tells Mikoto not to get ahead of herself and think that she's his wife.
- Cool Bike: Uses a Suzuki GS1200SS in Black Label ops.
- Expy: She resembles Rei Miyamoto from Triage X's sister manga. They're both hot headed, impatient tsundere's that are quite clearly in love with their male leads but the only difference is that Rei doesn't deny her feelings for Takashi while Mikoto does.
- I Call It "Vera": Her bike, known as "Black Goose" and her S&W M627, known as "Eight Ball".
- Meaningful Name: "Eight Ball" since her revolver has an 8-round cylinder.
- Ms Fan Service: In a realm of half naked action girls that are liable to clothing damage, this is a given. Mikoto gets special mention as we get several bath scenes with her and sometimes even Arashi.
- Revolvers Are Just Better: Uses a S&W M627 as her main sidearm.
- Miss Swears-a-lot: In the original manga, you can't go a single panel without this girl swearing her mouth off (usually at Arashi).
- Stripperiffic: If her outfit is anything to go by
. - Tsundere: Definitely a Type A towards Arashi that appears mostly in the manga while the anime downplays it.
- What the Hell, Hero?: Her reaction to Arashi not even batting an eye lash to shooting down Fujino when she attempted to attack him. Thankfully however, he only used rubber bullets to knock her out.
- Would Not Shoot a Good Guy: Or in his case, "Would Not Shoot A Non-Target". During the first encounter between Black Label and Pyrina a.k.a. Chikage Hizaki, Mikoto refrained from shooting the rival vigilante, who apparently would NOT have been so chivalrous if the initiative was reversed, because Pyrina has not yet been properly identified as a target.
Sayo Hitsugi
Despite her pleasant and attractive appearance, whenever Sayo is seen with her mask on her brutal and sadistic personality dominates her and she doesn't hesitate to cut down anyone that stands in her way. She's a close combat expert and can handle a variety of miniguns and machine guns. If that wasn't bad enough, she also possess monstrous strength and has a photographic memory, making her one of the deadliest members of the Black Label.
Little is known about her past except that its implied her father performed experiments on her body and as a result, Sayo became mentally unstable and killed him along with the other researchers. She then encountered Yuko during a mission and was cut down but then treated by Yuko who rescued her, which led to her joining Black Label.
- Ambiguously Bi: Sayo does find Arashi attractive enough to kiss in front of the whole team, but she's also shown to be similarly attracted to Yuko and Mikoto, the latter of whom she frequently teases (including biting Mikoto's ear at the hot springs). But unlike Chikage, it's not explicitly spelled out just how far her attraction goes for Arashi, let alone anyone else, so her sexuality remains mostly suggested, if not heavily implied, and not outright confirmed.
- Berserk Button: The sound or sight of metal utensils used to cause her to fly into a murderous rage since they remind her of the surgical tools her father used on her.
- BFG: Anything that Sayo uses be it a handheld Minigun or light machine guns, granted that she is The Big Girl of the team & also absolutely terrifying in close combat.
- Child Soldier: A side effect of what Dr. Itaru did when he used D99 to rescue his daughter due to an incurable disease.
- Cool Mask: She wears an Oni-like mask.
- I Call It "Vera": "Buzzsaw" for the MG-3 GPMG (After "Hitler's Buzzsaw", the nickname for the MG-3's predecessor, the MG-42) and "The No Pain" for the handheld minigun (in reference to "'Ol Painless' from Predator).
- Ms. Fanservice: In the OVA, she's wearing a skimpy outfit in the library.
- Mrs. Robinson: While she does seem interested in Yuko (28), Sayo (24) is more frequently shown expressing attraction to people younger than her, namely teenagers like Arashi (17) and Mikoto (17), with even an implied but begrudging interest in her Sitcom Arch-Nemesis Oriha (14).
- Self-Made Orphan: Killed her own father and his research team due to a side effect that made her go psycho with her physical strength boosted up.
- Wolverine Claws: Hitsugi fights with a pair of gauntlets with clawed fingertips.
- Worf Effect: Suffers from this when fighting against the Murasaki twins. Although she pays them back in their next confrontation.
Oriha Nashida
Oriha is a genius who started college when she was only 11 while in the United States and when she's not blowing things up during her missions, she acts as a teen idol performing concerts and acting. However, Oriha acts more of a child than she should and has gotten into the habit of giving her team mates nick names. Like some of the other members of Black Label, her history prior to joining the Black Label is shrouded in mystery. Oriha specializes in demolitions.
She lives at an abandoned mansion filled with explosive traps.
- Child Prodigy: Started college at 11 in America.
- Conveniently an Orphan: Is seen to be living in an abandoned mansion, loaded with explosive traps, the only "family" there for her is a large portrait of her mother. Her mother died after she gave birth to her.
- Disappeared Dad: Nothing is mentioned on what happened to her father.
- The Faceless: Uses a hockey mask to conceal her face when in Black Label ops.
- I Call It "Vera": "I☆DOL Buster", the name for her M79.
Yuko Sagiri
Yuko is one of the oldest and strongest members and has been implied to have been apart of the organization for quite along time. She is an attractive, kind, mature, and incredibly endowed woman that acts as a mother to the other members of the Black Label who all respect her talents.
During battle, Yuuko lives up to her reputation and uses her mastery of the sword to slay her enemies. For some reason, whenever Yuuko enters battle with her katana her hair changes to a snow white color. Its revealed that Yuuko fought against Sayo sometime in the past and saved her life, which caused her to join Black Label.
She has a sister named Yoko Sagiri.
- Ancestral Weapon: The katana known as the Orochi.
- Bullying a Dragon: Sure, go ahead. Try to sexually tease the unassuming doctor. She'll gladly take care of you... More specifically, take care of the entire upper half of you, along with any other lechers in her nearby vicinity with her razor-sharp katana.
- Childhood Friends: with Miki and Nao.
- Even the Girls Want Her: In episode 3, her masseuse expresses dissapointment she won't be able to massage Yuuko's chest.
- I Call It "Vera": The Orochi for Yuko's katana.
- Intimate Marks: Yuko has an Ampoule tattoo on her left breast.
- Lady of War: A graceful swordswoman in battle.
- Maybe Magic, Maybe Mundane: Her hair can change color.
- Ms. Fanservice: She has a very buxom figure which the series is not shy about exploiting.
- Sibling Team: Yuko fights alongside Yoko once she saves her from being killed by Algol and Mr. Astro.
- Statuesque Stunner: She stands at 5'8" tall and is one of the most attractive members of the team.
Miki Tsurugi
She is cool headed and acts as the voice of reason for her team in the midst of a crisis. She's the expert chemist and has impressive sniping abilities that benefit the Black Label. Miki is Mikoto's mentor and Yuko's childhood friend and as such is often partnered up with her during missions. She a is also considered one of its veteran members along with Yuuko.
She invented an anesthesia that works as a truth serum and the patient doesn't remember anything afterwards.
- A-Cup Angst: Doesn't like it when she sees other girls with bigger breasts than her. That also includes Yuko.
- Childhood Friends: with Yuko and Nao.
- The Faceless: Uses a SF-10 respirator to cover her face. Not present (a lot) in the anime adaptation.
- I Call It "Vera": "Silent Mist" for her Mk. 14 sniper rifle and "Indra Arrow" for the NTW-20 sniper rifle.
- Only Sane Man: Or rather, sane woman when Yuko and Sayo want to let Arashi in on their hot spring break.
- Sniper Rifle: Her Mk. 14 anti-personnel sniper rifle and the NTW-20 anti-material sniper rifle.
- Unresolved Sexual Tension: with Inunaki.
Masamune Mochizuki
A very serious man that commands a high degree of respect from his subordinates. He is usually seen in his headquarters and delivering out missions to his employees that follow his orders explicitly. He is in charge of deciding on whether criminals are given "black labels".
His son, Ryu Mochizuki, was Arashi's best friend, and after the terrorist attack, he was forced to declare his son dead. Seeing that Arashi was still alive despite the fact that his body was left in shambles, Mochizuki implanted his son's organs into Arashi's to save his life.
- Big Good: Runs the organization Arashi and the others are a part of. Does this due largely because of his son dying in a terrorist bomb explosion at a medical conference he was attending at the time. As such, he declares criminals to be a "cancer" on society, one in which the "medicine of law" has failed to "cure".
- He was also willing to take responsbility when he opened Mochizuki Hospital for refugees fleeing from the outbreak. He wasn't aware that Reika could take advantage of it.
- Hero of Another Story: Used to be a mercenary in his younger days.
- I Did What I Had to Do: He tells Arashi and Mikoto about a virus that had the ability to induce a Healing Factor in people, but also attacked the nervous system if the accompanying cure wasn't administered in time. While researching it, his team discovered it had great potential to save people's limbs, but could also be used for great evil if the virus was mutated, so attempted to destroy it. Arashi turns out to be the last person the virus was used on, and it was only because the chairman didn't want to lose both his son and Arashi after the terrorist attack on the medical conference. Arashi doesn't hold a grudge though, because he says he wouldn't be here today if not for the doctor's decision, and helping to protect people he cares about.
- Retired Badass: By the time the story, he has retired from his mercenary work.
- Taking the Bullet: Dies after he shoves Arashi out of the way and took a Hidden Blade stab to the chest in the 22nd volume.
- The Medic: Served as one with his fellow mercenaries.
Fiona Ran Winchester
The Director of Mochizuki General Hospital and a staff member of the Black Label.
Fiona is a calm and calculating woman; rarely interacting with the other members of the organization. She is usually seen standing by the directors side and debriefs the team on their objectives.
Its safe to assume that she can be considered the second in command of the group and seems to also be one of the older members of the organization along with Yuuko and Miki.
- Absurdly Youthful Mother: Volume 25 mentions that she's Ryo's biological mother.
- But Not Too Foreign: Appears to be of Japanese and Caucasian origin.
- Dark and Troubled Past: Volume 21 mentions that her family was killed outright with her being a sole survivor.
- Meaningful Name: In Japanese language material, her name (with a mixture of katanaka and kanji) has a reference to the Dutch via the kanji for ran, which usually means orchard. If you combine that with hito, meaning person, the full meaning of it (蘭人) means "Dutch people".
Isoroku Tatara
A dedicated but easily angered detective that works for the Police Force.
Isoroku is a very tenacious man that refuses to let anyone who he has set his eyes on get away. Unfortunately, this puts him at odds with the Black Label organization that constantly eliminate targets that he was instructed to bring in. .
Even though he is indebted to them for saving his life on multiple occasions, Isoroku's pride refuses to accept help from an outside source and he has vowed to track down Black Label.
Konomi usually acts as his assistant during investigations.
- Hot-Blooded: Of his time as a detective.
Konomi Suzue
She aspires to become a top detective and initially thought that Tatara would hold her back. Later on though, the two become a good team and accept each other's strengths and faults. Because of her inexperience, she has gotten herself captured several times and required someone to come save her.
Like her partner, she often comes across the members of Black Label at the crime scene but she doesn't see them in a negative light like Tartara. Though, she was understandably flabbergasted that her vehicle was destroyed as she hadn't finished payments on it.
- Blind Without Them: She can't see very well without her glasses.
- Fair Cop: She happens to be one.
- New Meat: She just started to work with the force.
Makoto Ogawa
A veteran detective in the Tobioka Police Force, who is the partner of Tamon Asakura.
- Defiant to the End: Despite being severely wounded by Mikoto, he grins and gives a warning that Black Label will be defeated.Ogawa: There will come a day when you realize that your ideals... are for nothing.
- Manipulative Bastard: He is "the Master" that Pyrina speaks of and has been taking advantages of her via falsely linking her sister's death (for which he is hinted to be responsible) to terrorism.
- The Mole: He works for Syringe.
- Walking Spoiler: It's hard to talk about anything about him without going to a spoiler.
Tamon Asakura
A no-nonsense veteran detective in the Tobioka Police Force. He is partnered up with Makoto Ogawa. He doesn't show up a lot in the anime adaptation.
- The Comically Serious: Always makes it a habit to prove that drinking milk is Serious Business.
Hinako Kominato
Kominato is a happy and cheerful young girl that tries to get closer to Arashi. Whenever she even so much as looks at him she gets visibly shy and flustered and has a hard time speaking her mind when he's around. Her classmate Momokino actively encourages her pursuit of him but Kominato finds Arashi to be too "cool" to date someone like her.
Her father owns the Monte Carlo SS café and she works their part time as a waitress. She will usually dress up in a maid outfit to impress Arashi and get him to notice her.
- Locked Out of the Loop: She's unaware of Arashi's vigilantism.
Yuu Momokino
Momokino is Hinako's best friend and acts like a big sister towards her, not hesitating to challenge someone who would bring harm to her. Though she didn't see what Hinako sees in Arashi, she supports her best friend in her puruit of him and wishes her the best and has come to accept Arashi as a friend.
She appears to work several part-time jobs to maintain her younger brothers. She has quite the impressive rack herself, rivaling that of even Yuuko and Suzue.
- Locked Out of the Loop: She's also unaware of Arashi's vigilantism.
Nao Sakurada
She is an attractive young woman that is implied to be a bit clumsy as some students took a picture of her falling down looking air headed. Nao also appears to be an understanding woman as she is aware of Arashi's frequent absences and doesn't seem to mind. The males of her class worship her because of her enormous rack and have obtained photos of her cleavage.
She was stated by one of the students to have the biggest breasts in the school.
- Badass Teacher: She's quite capable of defending herself.
- The Reveal: She's an ally of Black Label and an old classmate of Yuko and Miki.
Fujino
A pretty young woman that was taken hostage by Taisei and his men.
Fujino is a weak, fragile, but kind girl that got caught up in her father's mess and ended up being tortured by one of Taisei's men. She was rescued and treated, only to be kidnapped once again to be used by Masaki after being discharged from hospital.
- Brainwashed and Crazy: Drugged by Masaki into believing Tatara to be the one responsible for her father's death (when in truth her father was executed by Masaki) and then tricked into attempting to kill Tatara.
Ms. Kimura
An old lady that was a regular patient of the Mochizuki Hospital.
Pyrina a.k.a. Chikage Hizaki
Because her affiliation is unclear, and all her victims so far are criminals (although some are known only to have committed petty crimes), she is labeled a Fever, meaning Black Label organization has not yet deemed her actions as grounds for assassination despite her hostile encounter with Black Label operatives.
Becomes enrolled at Mochizuki High School shortly after said first encounter and befriends Mikoto Kiba, with neither of them being aware of each others' covert identities, after the latter saved her from school bullies. She lost her parents to the same terror attack that almost killed Arashi and then her little sister in an apartment fire, losses she never got over. Warms up to Mikoto quickly after the latter's display of empathy over her loss of family.
It later turns out that her master is the fake Makoto Ogawa, who has used her on behalf of Syringe.
- Ambiguously Bi: Subverted. She had a thing for her master once upon a time, but his actions in the present story completely killed those feelings on her part. Then we see her flirting with Mikoto near constantly after they become friends. At first it's not clear if she just enjoyed teasing Mikoto or if she was genuinely attracted to her. Chikage's return to the series clarified that she is attracted to Mikoto, making Chikage canonically bisexual.
- Because You Were Nice to Me: The reason she bonds so quickly with Mikoto is because Mikoto was genuinely upset to learn what happened to the Hizaki family, a level of empathy that Chikage never got from her sociopathic master.
- Boom, Headshot!: Pyrina is shot in the head with a crossbow bolt. Though she survives it, she commits suicide shortly afterward by jumping into the burning building.
- Expy: Chikage Hizaki, especially in her full color experiences, looks almost exactly like Saeko Busujima from Highschool of the Dead, Sato's previous series. If it weren't for the random tuft of hair on the side of her head that resembles a pointed up horn the characters would be almost identical.
- Eyepatch of Power: After being almost killed by Ogawa, she now wears an eyepatch to cover her right eye were she was shot.
- Heel–Face Turn: Inunaki was able to heal her from her injuries, so she fights by herself against Syringe and joins with Arashi and the others.
- The Immodest Orgasm: Both the manga and anime show her screaming in pleasure while having sex with her master Makoto Ogawa.
- Kill It with Fire: Her primary assassination method; all of her weapons can be loaded with incendiary ammunitions. Her combat knife's blade can burn things up.
- Never Found the Body: In manga, after her apparent suicide- her equipment was recovered, but no body was identified as hers. In anime she is simply not mentioned again afterward.
- Not Quite Dead: After being presumed dead since volume 4, she turns out to be alive in volume 16.
- Sex for Solace: She was depressed after losing her family at such a young age, understandably so. Her master kept having sex with her to help out, but it predictably never worked for long.
Kaname Makiishi
One of the leaders of Syringe. She ultimately answers to Reika Azuma.
- Arc Villain: She replaces Wild Hunt as the main antagonist after Arashi kills her until Azuma shows up.
- Batman Gambit: Responsible for masterminding the events of the Neo TV arc alongside Siren so that they can easily into the servers of the Tokyo Metropolitan Police's Public Security Department.
- The Cracker: Her specialty within Syringe.
- Would Hurt a Child: Or rather, hacks a Tobioka City shelter and allows the D99 zombies to kill men, women and children inside.
D
A masked man in a balaclava. He's on the few members of Syringe to have Jet Injector used on him to survive his injuries and have enhanced strength.
- Cold Sniper: Gladly takes out anyone who's an enemy of Syringe.
- Die Laughing: He dies after the hotel is demolished, dying from a fall.
- Although he shows up again when Reika raids Mochizuki Hospital in the 20th volume.
- Killer Cop: It's revealed in Volume 21 that he was an ex-police officer named Inspector Shinsaku Inui, who led the attack on the medical conference.
- The Faceless: He wears a balaclava.
- The Brute: Uses his strength alongside martial arts to take an advantage against his opponents.
- The Reveal: Volume 13 suggests that he has intimate knowledge on what happend to Arashi after the medical conference was attacked.
- Would Hit a Girl: D has no qualms on shooting or hitting girls/women. Especially if it helps rile up Arashi.
Mr. Astro
A masked man who provides muscle for the group.
- The Brute: For Syringe, being the biggest and physically the most powerful in the group.
- The Faceless: He wears a balaclava with a skull on it.
- Sharp-Dressed Man: He wears a tie and suit, even when masked.
Algol
Another muscular man who fights with Mr. Astro later on when Tobishiro is under a state of emergency.
- The Faceless: Wears a mask.
Kaori Murasaki
One of two females in Syringe, responsible for unarmed combat in close quarters alongside Kaoru.
- Fiery Redhead: Has red hair and is a relentless fighter.
- Foolish Sibling, Responsible Sibling: She's more focused than her twin sister.
- Sibling Team: Is one for Syringe alongside Kaoru.
- The Faceless: Wears an oni-type mask.
Kaoru Murasaki
One of two females in Syringe, responsible for unarmed combat in close quarters alongside Kaori.
- Foolish Sibling, Responsible Sibling: Kaori usually has to keep her focused.
- Heel–Face Turn: By Volume 23, she joins with BL in order to find her sister before Syringe kills her.
- Sibling Team: Is one for Syringe alongside Kaori.
- The Faceless: Wears an oni-type mask.
Wild Hunt a.k.a. Siren
A masked man who leads a group of well-trained mercenary terrorists on behalf of Syringe who is later revealed to be a female.
- Arc Villain: The main antagonist of the Neo TV arc.
- First-Episode Twist: The first episodes of the anime adaptation shows Wild Hunt's true gender, thus spoiling the surprise unlike the original manga work.
- Samus Is a Girl: In the Neo TV arc, Wild Hunt is revealed to be a woman named Siren, who can change her voice by manipulating her throat.
- Western Terrorists: According to a manga omake, Wild Hunt was recruited from Eastern Europe.
Taisei Aranami
The heir to a wealthy fortune. Took over his father's company after Arashi assassinates him.- Big Bad Wannabe: Alongside Jin Masaki in taking over his father's group. He fails.
- Boom, Headshot!: Arashi shoots him straight through the head with his gun.
- Lean and Mean: He's lanky and is a villain.
- Tempting Fate: Likes to gloat about being well-connected like his father... after the latter is assassinated. It does him about as much good as it would any Villain of the Week.
Jin Masaki
One of Taisei's advisers. He happens to be the family lawyer.- Amoral Attorney: In the service of the Aranami family.
- Better to Die than Be Killed: After his Gunship Rescue gets shot down by Black Label, he attempts suicide, but it fails.
- Big Bad Wannabe: Wants to be this in the beginning of the manga via manipulating Taisei. Like Taisei, he doesn't make it.
- Impaled with Extreme Prejudice: His suicide is interrupted when he falls on the rotor blades of the downed helicopter after Arashi derails his suicide declaration.
- Killed Mid-Sentence: He is shot by Arashi in the middle of his Defiant to the End statement.
Kyoji Tobishiro
The sadistic son of the head of the highly influential Tobishiro Clan, who is interested in acquiring the drug known as Platinum Lily.- Hate Sink: He is devoid of any redeeming quality and is pretty much sustained by nothing but Plot Armor.
- Too Dumb to Live: He is aware of the effects that Platinum Lily, which is laced with D99, has on people but wants to spread it on the street for profits anyway, believing that his father's influence will protect him from any consequence imaginable. The city-wide D99 outbreak comes to pass because his unwilling Human test subjects escaped and then start attacking civilians after being driven insane by the virus. The fact that this imbecile has managed to survive thus far has nothing whatsoever to do with what little useful attribute he might possibly have possessed.
Yoko Sagiri
The sister of Yuko Sagiri, she's feared in the underworld for her katana skills.- Big Damn Heroes: Saves Yuko from being killed by Algol and Mr. Astro in the 20th volume.
- Dark Action Girl: Yoko works in the underworld and has a tattoo on her back, symbolizing her yakuza affiliation.
- The Dreaded: The underworld is scared of her for her katana skills. She's known as "Demon".
Ryu Mochizuki
The childhood friend of Arashi and the only son of Dr. Mochizuki. He's the victim of a bombing attack that targeted an international medical conference that he was attending.- Posthumous Character: Is dead by the time the series starts, but his "spirit" hangs around Arashi.
- Spirit Advisor: Helps Arashi figure things out when he's in doubt.
- Walking Spoiler: His full backstory's hard to talk about without knowing that his mother is Ran.
Togu Itaru
A brilliant doctor recruited by Doctor Mochizuki to help analyze the effects of D99. Prior to the events of the story, he went rogue and escaped with some samples of the virus.- Posthumous Character: He died after the story began.
- Well-Intentioned Extremist: He wanted to save his daughter, Sayo, from dying when he used D99 on her.
Reiko Azuma aka Reika Togo
- Big Bad: She’s the one ultimately responsible for everything Black Label fights against in the whole series.
- Boom, Headshot!: Arashi shoots her in the head rather than allowing her to hide with Fiona's body in order to dissect it and do research.
- The Dog Was the Mastermind: You'd never realize that a disabled high school student like her would be the mastermind of a major criminal organization.
- Evilutionary Biologist: She claims her motivation for her atrocities is to further human evolution.
- Hero Killer: During the raid on Mochizuki Hospital, she shoots Fiona at the neck with a SAA revolver. Volume 21 reveals that she's alive due to a prototype chip implanted in her.
- MsExposition: Loves to give these once her plan sees her revealed as the Big Bad of the series.
- Revenge: Reika imples that Mochizuki could be thinking about why she raided the hospital. She spelled it out that she's looking for a chemical codenamed "Chaos".
- Villain with Good Publicity: Reika's a known honor student.
- Well-Intentioned Extremist: She wants to get rid of the corrupt elite within the city by targeting the hotel they're using as a refuge.
Lady Dire
- Bad Boss: She killed a subordinate for barging into her room in order to warn her of an attack, just because they didn’t have permission. In her own words, anyone who doesn’t obey her rules (regardless of the reason) are as good as corpses to her.
- The Baroness: Both a Sexpot and Rosa Kleb version. She’s frequently shown near naked to emphasize both her beauty and toned physique, and is seen being tended to by blindfolded, half-naked men wearing leashes. She’s also seen brutally slaughtering subordinates for minor offenses.
- Best Her to Bed Her: Subverted. After Arashi defeats her, she claims this is a tradition of the women in her family. In reality she plans to poison him as soon as he drops his guard. Arashi being Arashi wasn’t even paying attention to her offer.
- Greed: Her sole motivation for teaming up with Reika, is for purely monetary value. One panel even has her imagine bathing in cash.
- Luckily, My Shield Will Protect Me: In her fight between Arashi and Mikoto, she wields a shield as large as she is that can stop their bullets without a scratch. It also shoots lasers.
- The Man Behind the Man: She's responsible for bankrolling Syringe and Reiko.
