Spark Signal

Spark Signal is one of Academy City's dark side organizations whose level of secrecy is similar to that of Hound Dog or.

Principles
Spark Signal was created for the purpose of dealing with people from Academy City that would try to sell out secrets towards the outside world.

The group's strategies are founded on the concept that "espers are still human", aiming to create viable countermeasures by properly analyzing the enemy tactics and taking advantage of their "human weakness", so when facing espers that can create incredible phenomena they can still respond appropriately: "First calmly analyze the opponent, then find a way to defeat him". Their battle tactics were of no use against Accelerator's cold, efficient and ruthless assault and the main group was completely decimated by the Level 5 in 300 seconds.

In the same fashion as Hound Dog, Spark Signal displayed tactics which included only warfare strategies and regular weapons instead of the usage of espers or customized prototype weapons.

Spark Signal's approaches to Electromasters, seen during an inadvertent clash with Misaka Mikoto, include switching their electronic gear to manual to avoid hacking attempts and utilzing insulated gear while buying time to set up traps. During this clash, they also made use of a flash grenade, tear gas and.

Background
In their activities, Spark Signal have apparently fought with powerful espers countless times. In the 'Remnant' incident, Musujime had contacted people outside of Academy City. For all she knows they probably have already fought with Spark Signal.

First Year Arc
At some point late in the year prior to the main story, Spark Signal was pursuing a certain organization as part of their overall mission. After arresting a low-level courier, who didn't know anything that could lead back to the main group, they found a list of Academy City students they hoped to recruit as industrial spies, one of which was Konoe Nagisa, who had expressed interest in the offer and contacted low-level members several times. They planned to intervene when she was set to meet a top-level member of the organization, in order to get enough information from them to take down the whole organization.

On the day of the meeting however, Konoe was approached by Shin'enkouji Rurikakesu for information on a case she was working on, with agents observing the meeting from afar, and Misaka Mikoto and Kessai Kiyoshi secretly following to observe Ruri's Judgment work. Spark Signal ended up mistaking the girls for members of the organization, and proceeded with their mission despite the assumed contact having happened earlier than they anticipated. Bursting in on the girls in an abandoned building, one unit fired on Konoe as she attempted to flee, though Ruri's ability protected her from serious harm. While that unit ended up facing Mikoto (who had retaliated in response to the ambush) and Kessai, the other unit intercepted Ruri and Konoe after they became separated from the other two, with Ruri enabling Konoe's escape.

The unit facing Mikoto ended up focusing on buying time and setting traps, including tear gas and blade wires, but she was able to overcome them with her ability and some help from Kessai. The pursuing unit used more direct combat means, while Ruri fended them off with a combination of precise ability usage and martial arts. Despite being pushed into a narrow alley, Ruri was able to bloody and knock out several members of the squad.

Eventually, Spark Signal aborted their mission after confirming with Judgment HQ that Ruri was really one of them, with the latter being given a short and minimal explanation of who they were and what they were doing. Although they failed to take Konoe, their leader believed they would track her down with a Telepath's help and saw the battle as excellent combat experience, recognizing the need to update their combat doctrine for high-level espers in light of the trouble they had.

DRAGON Arc
By October 17th, they had revolted against Academy City and started a strange seizing operation incident where they occupied the world's largest particle accelerator situated inside the city, the Hula Hoop. They would hold around 30 primary school students hostage, captured from an astronomy field trip; along with their teacher and driver, they acted as a ‘bargaining chip’ for use against the higher ups.

The group carefully made the plan that included the Hula Hoop and put into it all of their efforts and resources; the demand that they made to Academy City was "disclose all of the information you possess about DRAGON". later noted how ironically the higher ups used them to get rid of a team whose purpose for rebelling resembled their own hidden agenda.

After the main team from Spark Signal was taken out by Accelerator, a group of survivors tried to escape and rethink their strategies from the start; for that reason was tasked with chasing down the remnants and dealing with them ; the person who directed  also gave orders to Kinuhata Saiai's new team to finish them off. While the Spark Signal survivors were executing their plan to escape, they were first attacked by Tsuchimikado Motoharu, Musujime Awaki and "Unabara Mitsuki" from, and then after escaping them, they took hostages in a private salon in School District 3. One of the hostages was Takitsubo Rikou and thus Hamazura Shiage decided to jump into the fray and stop them; his attack would gravely impair many of the Spark Signals survivors. While Shiage was breaking into the building, the pursuing Accelerator finally caught up with the remaining Spark Signal survivors and proceeded to defeat them all. After he was done, Sugitani appeared and killed all of the fallen members of Spark Signal.

It should be noted that Kinuhata Saiai from could not engage the survivors from Spark Signal in battle, since Stephanie Gorgeouspalace contacted Spark Signal and offered her help in dealing with her, an act which kept Saiai busy by the time when Shiage and Accelerator were raiding the private salon.