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 GROUP.

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.

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.

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". GROUP 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 GROUP was tasked with chasing down the remnants and dealing with them ; the person who directed ITEM 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 GROUP, and then after escaping them, they took hostages in a private salon in 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 ITEM 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.