Dark May Project

The Dark May Project (暗闇の五月計画) was an experiment carried out in Academy City, aimed at replicating Accelerator's powers by implementing similar patterns of ability operation.

Principles
The Dark May Project was an experiment which used young esper test subjects, most likely Child Errors, using various means to influence and test the subjects' brains. The objective of the main project was to replicate Accelerator's powers by implementing his thought patterns into the test subjects. Consisting of over 40 test subjects for the project, only the top elites among them had Accelerator's thought patterns implanted into them, with prior screening to determine whether candidates were suitable. Kinuhata Saiai stated that it wasn't usual for children of the experiment to end up well, as many of them ended up in dissection tables while scientists tried to figure out in which part of the brain the Personal Reality was located.

Main Project
The Dark May Project's main objective was to replicate Accelerator's powers by using a similar pattern of ability operation. This was done by referencing the cognitive patterns of Accelerator himself, in order to optimize the Personal Realities of the espers taking part in the primary experiment, the top elites among the test subjects.

The exact method(s) which were used in the implantation are not clear, but Accelerator's thought patterns were implanted into the test subjects, with specific portions of his thoughts, feelings and beliefs (such as Pride, Suspicion and Attachment) being implanted into different subjects to observe their specific effects, and ultimately in the hopes of improving the subject's esper ability development. One of the after-effects of the implantation is that Accelerator's personality may be ingrained into the subject, with Kuroyoru Umidori and Yuzuriha Ringo exhibiting such side effects. The implantation would also result in a number of operational similarities to Accelerator - in the case of Kinuhata Saiai, it taught her to use her ability as an automatic self-defense capability that activates if she is attacked, similar to Accelerator's vector shield.

After successfully implanting the Accelerator's thought patterns, the researchers would then begin brutally testing their test subjects to see if their esper powers have gone through any changes or improvements, using highly painful and brutal methods. In the case of experimentation on Yuzuriha Ringo, various painful stress-inducing tests and drugs were used in order to stimulate her brain and force her esper powers to improve its "values". These extremely traumatic tests in turn left her severely injured on a daily basis and resulted in Ringo developing several gaps in her memory due to the trauma and stress. Later, the researchers were even willing to go as far as using severe psychological torture on Ringo in order to stimulate her implanted sense of "attachment" from Accelerator, by physically abusing her friend Ryuugou Tomoka right in front of her and chaining her to the wall to stop her from helping her, in order to gather more data on her power's ability to improve when she was put under immense stress and psychological pain.

One of the project's labs, abandoned after the project's failure, is located below a confectionary, built on land bought cheap on the condition that the factory never searched underground. The main facility had a hidden room, containing over 40 cold sleep pods, about the size of a phone booth and using a bio electrolyte gel as a cold sleep medium, which test subjects could be stored in.

Variations
Besides the main Dark May Project involving Accelerator's thought patterns, there was at least one "variation" of the project with a similar yet different approach. Located in a separate laboratory from the main project and run by a sub-team, it was the facility which Child Errors Shundan Kimi, Tsurigane Saryou, Wanigawa Raifu and Shirakinu Honoka were given to in exchange for a loan for their financially-struggling orphanage, under the guise of a "power boosting lab". The group were screened for the main project but did not pass the primary screening phase.

Rather than the obstensible goal of boosting the subject's esper abilities, the experiments at the laboratory involved surgically tampering with specific areas of the test subjects' brains and observing the effects on the subject's abilities, in order to determine how modifying those specific areas influences abilities. During the course of the experiments, Raifu's ability rose from Level 1 to 3 in less than two years at a cost to her mental state and with pronounced post-testing effects while Honoka's ability was diminished from Level 2 to 1 to practically nothing, with the effects of increased irritation and anger. Tsurigane's ability was also advanced with some apparent side-effects,   while Kimi lost her sense of taste, with a subsequent loss of feeling likely due to a combination of the experiments and the trauma experienced during the eventual escape from the lab.

Aside from performing surgical modifications to the test subjects' brains and monitoring the effects on their abilities, including measurements of their AIM Diffusion Fields, the facility's equipment was also capable through some means of reproducing changes in those AIM fields and their effects to a certain degree, and the facility also had access to data from astronomical observations, evidenced by the discovery of a small black hole forming at the same time as a change in Kimi's AIM diffusion field and the subsequent reproduction of that phenomena after discovering the connection.

The facility was managed by a separate team of researchers from the main project. Although meant to report their findings to the main team, the circumstances surrounding Shundan Kimi's unique power led to information being withheld regarding their discovery and the continuation of experiments regardless of previous discussion, playing a part in a resulting schism, with the head researcher seeking to retain and explore the possibility regardless of risk, and his subordinate recognizing the dangers shooting him dead before intending to take advantage of the main lab's ignorance to kill Kimi and cover up the murder. Aside from the researchers, at least one of whom carried a gun, there was also a management team of armed guards. Besides the armed personnel, the facility possessed security robots known as Spriggans, programmed to capture targets.

Background
The exact time period over which the main Dark May Project was run is not known, though it is known to overlap with Accelerator and Kakine Teitoku's continuing tenures as #1 and #2 Level 5 respectively. At some point during the project, the test subjects were shown footage of Kakine. At another point, Kihara Amata and Kihara Souji visited the facility, around the time of Ryuugou Tomoka's death as an end result of the researchers brutalizing her in front of Yuzuriha Ringo as part of an experiment to force Ringo's power's values to raise. The Dark May Project was supposedly brought to an end when Kuroyoru apparently killed all the researchers, bankrupting the project, though  had actually framed her after they were hired to kill the researchers and destroyed evidence, ahead of an Anti-Skill raid on the project facility.

The exact time over which the main project took place is not known, but activities of the project's variation occurred over a period of more than a year somewhere in the time period between nine to three years prior to the main story. Having obtained four Child Errors (Shundan Kimi, Shirakinu Honoka, Wanigawa Raifu and Kouga infiltrator Tsurigane Saryou) from an orphanage in exchange for a loan and under the pretext of a power boosting lab, they carried out experiments on the girls' brains with varying effects.

On noticing abnormalities with Kimi's ability, the lab investigated it and eventually discovered its true nature of creating a black hole, with the head researcher keeping the main lab in the dark so as not to lose their specimen. However, a schism developed among the research team due to the risks posed by Kimi's power, with researchers who believed it to be too dangerous to continue the experiments or even let her live, while the head researcher didn't want to throw away the potential. This ended with the head researcher being shot dead by his subordinate who then planned to murder Kimi under the guise of an accident during brain surgery, taking advantage of the main lab's ignorance and planning to cover it up. Having learnt of the conspiracy, Tsurigane informed the others and they fled the facility (who had intended to kill the escapees), with Tsurigane killing the staff and burning the building down after them, though Honoka was killed during the escape. The three survivors were left scarred by these events.

Enemy Arc
On the night of June 30th, one year before the main story, the then-three-person ITEM was hired to eliminate evidence at the Dark May Project facility, ahead of an Anti-Skill raid (with Yomikawa Aiho involved). During their mission, they discovered a hidden room with the cold sleep pods containing the project's test subjects. Rather than eliminating them as they had done to the researchers, Mugino Shizuri decided to recruit one of them for her team and selected Kinuhata Saiai from the project's two main successes. Shortly after Kinuhata had been released from her pod, with Anti-Skill approaching, Mugino had Frenda Seivelun set Kuroyoru Umidori's pod to thaw at a slow speed with the intent for her to take the fall for them, with Anti-Skill to assume that Kuroyoru had snapped and destroyed the lab while dazed from the thawing process.

Battle Royale Arc
When Kakine Teitoku brought up Kinuhata Saiai being a former test subject of the Dark May Project, she mentioned that she was super happy compared to the test subjects of Produce who had their brains chopped up like a Christmas cake.

World War III Arc
The Dark May Project was mentioned during Accelerator's discussion with Misaka Worst after their arrival in the Elizalina Alliance of Independent Nations. Although Worst hadn't warmed up to him for sparing her, the Level 5 urged her to cooperate in looking for better leads related to the parchment pieces. Worst refused, but Accelerator reminded her that her fate as a clone would be the same because they would remain disposable unless something was done. The Third Season clone stubbornly remained uncooperative until Accelerator opened a possibility for her to be useful through the Dark May Project. Misaka Worst saw it a worthy opportunity and decided to agree.

Freshmen Arc
When they met, Accelerator told Kuroyoru Umidori that he had once eliminated Academy City's dark side and wanted to know why her dark organization was still active. Kuroyoru replied with anger that not everyone in the world would just get along with one another. Accelerator realized that she was a subject of the Dark May Project after observing her pattern of calculation and manner of speaking.

Jailbreaker Arc
The events surrounding the Jailbreak Trial involved the survivors of one of the project's variations, particularly Shundan Kimi with Tsurigane Saryou and Wanigawa Raifu abetting, and were heavily influenced by the events which had transpired at the lab in the past and their after-effects.

Following Tsurigane's betrayal of the Kouga, Oumi Shuri learned of her involvement in the Dark May Project and its apparent role in her transformation.

Yuzuriha Ringo Arc
Kakine saved Yuzuriha Ringo from a bunch of thugs because she was one of the survivors of the Dark May Project. Yobou Banka found out about more survivors to contact, but Kakine refused the offer so as not to be detected. His goal was not to fight with Accelerator, but he wanted to know Accelerator's calculation pattern for an unknown reason.

Another survivor of the project, Kuroyoru Umidori, was involved in the events which followed, picking a fight with Yuzuriha Ringo at one of the project's abandoned labs, below a confectionary. In the aftermath of the conflicts over her with Kuroyoru, DA and Kihara Souji, Ringo died from a self-destruct mechanism slipped into the program implanted in her brain.

Main

 * Kinuhata Saiai
 * Kuroyoru Umidori
 * Ryuugou Tomoka (deceased)
 * Yuzuriha Ringo (deceased)

Variation

 * Shirakinu Honoka (deceased)
 * Shundan Kimi
 * Tsurigane Saryou
 * Wanigawa Raifu