Academy City is a state-of-the-art city famed for developing technology 20-30 years ahead of the rest of the world, the most famed of which are espers — adolescents who possess Psychic Powers.
But Academy City is far from the utopia it presents on the surface. Several inhabitants of the city are a part of its "Dark Side", a criminal underworld that freely engages in illegal activities including assassination, espionage, experimentation, among other enterprises.
One of these inhabitants is Teitoku Kakine, leader of the Dark Side organisation "SCHOOL". He is a Level 5, the highest level rank currently achievable by an esper, and is overall ranked #2. His power is Dark Matter: The power to create new matter that doesn't exist in the physical world and thus doesn't need to follow its laws, allowing him to create whatever effects he can conceive with it. Teitoku is gathering data about the calculation patterns of Academy City's #1 ranked esper in order to get around his Attack Reflector in the lead up to their eventual clash. To do so, he tracks down Ringo Yuzuriha, a little girl who is a survivor of the "Dark May Project" which resulted in said calculation patterns being embedded into her, while trying to keep her safe from other members of the Dark Side.
A Certain Scientific Dark Matter, illustrated by Nankyoku Kisaragi, is yet another Spinoff written by Kazuma Kamachi that exists in the same universe as A Certain Magical Index. The manga is comprised of four chapters in total, dubbed the "Ringo Yuzuriha Arc", though only its first chapter was published to Dengeki Daioh in August 2019 with the full volume releasing in March 2020. Unlike Index's other manga spinoffs, Dark Matter is tied directly to the main canon of Index, with the events of the volume acting as a prelude to the Battle Royal Arc (Index Volume 15) and Teitoku Kakine's eventual duel against Accelerator.
Tropes found in this series
- Abandoned Laboratory: The Dark May Project lab. Which is underneath a Confectionary Factory.note
- All for Nothing: Teitoku ends up failing in most of the goals that he has in this arc. Not only does he fail to keep Ringo alive, the data he gets out of her end up being for naught since Accelerator is able to adapt his Reflection to Teitoku's Dark Matter during their fight anyway.
- Big Bad: Souji Kihara.
- Book Ends: Ringo asks Teitoku for food at the start and end of the manga. She also tells him that his wings are pretty at the start and at end as she dies in his arms.
- Brainwashed and Crazy:
- The DA agents whom Souji Kihara makes loyal to him. Then again, they were always crazy to begin with.
- Souji does it to Ringo as well, pitting her against Teitoku.
- Broken Bird: Ringo Yuzuriha. She was experimented on for a good while as part of the Dark May Project, being forced to take drugs and undergo psychological stress to see if her power has increased, the results of which causes her to develop Superpowered Evil Side where she blacks out and doesn't remember anything she does while she's in it. Even worse, the first time this side awakens, she ends up killing her best friend in the crossfire.
- Brown Note: The antagonists sometimes play noise at a tuned volume and frequency to raise Ringo's stress levels, causing her power level to jump.
- Bullet Holes and Revelations: After Teitoku successfully saves Ringo, a few panels later we're treated to a panel her recoiling and one of a handgun being shot by a Not Quite Dead Souji... Fortunately, it turned out that Teitoku blocked the bullet (and all shots thereafter) with one of his wings and finishes Souji off properly.
- Call-Forward: Souji Kihara's specialises in cybernetic prosthetics. Umidori ends up finding one of his old storage houses and takes an interest in what he's produced. Come NT1, she mentions that she's integrated 'Kihara technology' into her cyborg body.
- Cloud Cuckoolander: Ringo's not particularly well-adjusted socially. When she first gets "rescued" by Teitoku, she falls asleep. Right after he just strangled her. Her response to Umidori saying (via flying drone) that she knows her is "I don't know any flying boxes."
- Continuity Cameo: Several characters from other works in the franchise show up in this series.
- Accelerator, Last Order, and Esther appear in a panel, showing that the events of Dark Matter takes place at the same time as the Necromancer Arc of A Certain Scientific Accelerator. Likewise, Disciplinary Action (DA) show up as Mooks trying to capture Ringo.
- Umidori Kuroyoru, first introduced in NT1 of A Certain Magical Index as another survivor of the Dark May Project, is the first major antagonist contended with. Saiai Kinuhata also cameos during a flashback to the project in Chapter 4.
- Souji is seen talking to Amata Kihara a few times. Apparently, the latter is "heartbroken" to hear that Accelerator had been shot and suffered brain damage.
- Dark Matter happens before the events of the Dream Ranker Arc featured in A Certain Scientific Railgun, so all the original members of SCHOOL show up, though Rakko Yumiya only appears in the ending.
- Continuity Nod: After questioning a DA member, Kaibi Gokusai references their recent attack on Accelerator at the District 7 Hospital. Last Order is also seen telling Esther about what to order from the family restaurant they eat at.
- Darker and Edgier: Compared to most other stories that take place in the franchise, this story is quite grim and stays like that throughout the entire volume, not even dipping into franchise tradition of lightening the mood with Fanservice or Slapstick humour.
- Decision Darts: A variant. While relaxing in their hideout and planning their next move, Teitoku is seen playing darts. Banka asks if they want to track down another survivor of the Dark May Project considering Ringo's...eccentricities, but Teitoku prefers to work with what they've got. To emphasise his point, he throws a dart which pierces a picture of Ringo stuck to a corkboard.
- Diabolus ex Machina: Ringo's Self-Destruct command, which is apparently completely different to the other commands implanted by Souji into her, so much that SCHOOL isn't able to do a thing about it. It's later implied that Aleister Crowley (or someone on his level) was responsible for it.
- Doomed by Canon: Considering Ringo doesn't appear at all during the events of the Battle Royal Arc, not even getting a mention when Teitoku meets another Dark May survivor in Saiai Kinuhata, savvy readers would be suspicious of her chances of survival.
- Downer Ending: Ringo is freed from her mind control, Souji Kihara is dead, and SCHOOL is safe back in their hideout. Everything looks to be going fine, until Banka notices a kill command activate in Ringo's data that shuts off her internal organs, killing her.
- Dramatic Irony: Teitoku's final lines in the manga, alongside SCHOOL, is him refusing to accept the idea that they're fated to have those precious to them ripped away and swearing to resist his (likely meaning Aleister's) influence. Readers of A Certain Magical Index will already know that two of SCHOOL's operatives end up being killed by ITEM, and Teitoku himself never gets his audience with Aleister since Accelerator defeats him when they fight and leaves him near dead.
- For Great Justice: DA's catchphrase, as usual. Souji is able to take their obsessive dedication towards justice and 'substitute' it so they become his obedient servants.
- Genre Blindness: The Dark May researchers when they choose to torture Tomoka Ryuugou, Ringo's friend from her backstory, in front of her eyes while she's chained up in an attempt to stimulate her 'attachment'. Jumps straight to Too Dumb to Live territory when they decide to keep going when they see her power output rising, which eventually causes the room around them to collapse. Amazingly, they actually survive by tasering Ringo at the last moment.
- Kick the Dog: When they first get involved in the plot, we see a DA agent forcibly try to take Ringo away and "rehabilitate" her. When she refuses, he punches her in the stomach. This then allows Teitoku to wipe the floor with them without the audience feeling bad.
- Kill the Cutie:
- Tomoka Ryuugou, Ringo's friend from the Dark May Project, ends up dying after Ringo's power goes out of control in response to her being tortured.
- Ringo herself dies at the very end of the manga.
- Hit Me, Dammit!: Teitoku gets Banka to demonstrate what a higher-level version of Telekinesis looks like to Ringo by getting Banka to attack him. Thinking that he hurt Teitoku, Ringo responds by kicking Banka in the shin.
- Heroic RRoD: Ringo's body isn't adapted to using her power at high levels. When she's Brainwashed and Crazy, she's able to use her Telekinesis to move at high speeds to keep up with Teitoku but her body slowly becomes more and more injured from the G forces, something that Teitoku notes wouldn't happen to Accelerator.
- Journey to the Center of the Mind: To free Ringo from Souji's control, Teitoku uses Dark Matter to communicate with her by manipulating sound and light in a way that'd allow her to break free.
- Morality Pet: Ringo to Teitoku. Likely because she reminds him of another friend who died when he was younger.
- Neural Implanting: The whole point of the Dark May Project. By implanting Accelerator's thought patterns and calculations into Child Errors, scientists involved were hoping to see whether their powers could be artificially increased. For those who were successful in the project, Ringo included, their power level jumped up to Level 4 (the highest possible without approval from the city's leadership) while their powers were molded to resemble Accelerator's Vector Control as a byproduct. Teitoku hopes to exploit this to find a blind spot in Accelerator's ability.
- Production Foreshadowing: A blink and you'll miss it moment. After Ringo mentions that the project was stopped because Umidori went berserk and killed all the researchers, Banka notes he didn't find any records about it. Toaru Anbu no Item would later reveal that ITEM (then only Shizuri, Frenda, and Rikou) were actually responsible for shutting down the project, using Umidori as a scapegoat.
- The Power of Creation: Dark Matter. When Teitoku uses it, he's able to create new matter not bound to the laws of the physical universe, making it almost akin to an Imagination-Based Superpower. When he uses it against Souji, Souji counts over 3300 new phenomena occurring in their localised area.
- Recurring Element: Like Touma and Accelerator, Teitoku meets a little girl who has important knowledge stored in her brain and takes her in after feeding her. He misses the part where he accidentally strips her though.
- Reduced to Dust: Souji Kihara's eventual fate after Teitoku uses one of his wings to slice through him.
- Running Gag: Ringo's Growling Gut and asking for food.
- Showy Invincible Hero: Basically nothing in this story is a threat to Teitoku, given that he's the most powerful esper in Academy City just under Accelerator while not suffering the latter's Drama-Preserving Handicap. The only time he does get hit is when he's fighting Ringo, and that's only because he's deliberately holding back so as to not hurt her.
- Superpowered Evil Side: Ringo's power is Telekinesis, but under normal circumstances is only on the level of around Level 1 (i.e. just enough to slightly move a small pebble). Due to the Dark May Project, her power jumps dramatically to Level 4 under stress, and when it does her personality flips from a soft-spoken Shrinking Violet to being Ax-Crazy much like Umidori. It's because having Accelerator's thought processes implanted into her resulted in her personality changing to be similar to his.
- The Ax-Crazy part disappears when Souji brainwashes her to bring out her full power., at which point she continuously uses her power at max potential that's even enough to fight Teitoku, remaining dead silent throughout the fight.
- Underestimating Badassery: Several times, Teitoku's opponents will crow that there's nothing he can do to interfere with the situation at hand because they have equipment that is made to repel esper powers. When he eventually gets fed up with the prattle, he smashes right through it.Teitoku: Don't underestimate a Level 5.
- Villain Protagonist: The manga focuses on Teitoku Kakine (and SCHOOL, by extension), and directly ties into his goals as one of the main antagonists in Volume 15 of Index. That said, the manga shows off more of his backstory to show why he turned out the way he has, he's by far at his most personable here thanks to Ringo, and the antagonists he faces are definitively eviler than he is, pushing him into Anti-Villain territory.
