Attachment Dark Matter

Attachment Dark Matter (アタッチメントダークマター) is a prototype weapon and attempted scientific reproduction of #2 Level 5 Kakine Teitoku's Dark Matter, developed and utilized by Antikythera and Montgolfier.

Principles
The development of Attachment Dark Matter arose from a biological specimen from Kakine Teitoku in the past, which Antikythera managed to acquire. The ultimate objective was a scientific reproduction of the #2 Level 5's Dark Matter. However, the original specimen's quality was nowhere near the current Kakine, creating a fundamental roadblock in the development, along with the sample's quick deterioration. As capturing the real thing was not possible, Antikythera instead chose to analyze many different esper powers from multiple angles in an attempt to overcome this roadblock. Antikythea provided funding and downgraded data to Montgolfier, in exchange for test results and observational data from the manufactured prototypes (supposedly obtained from the instigated inter-clique conflict).

The weapon system is integrated into a dark full-body suit with a light-colored mask worn by the wielder, mounted on the arms and back. There are two versions; a lighter model with a compact design for mobility and weapons solely mounted on the arms, and heavier units, supposedly with greater precision and firepower and additional weapons extending from the backpack.

The masks have communication equipment and an air supply. There are multiple receivers on the mask and the arm-mounted weapons, which can receive encrypted communications transmitted through Mitarai Ayane's ultrasonic waves. The suits will not short out from a basic drenching, but the machinery is still susceptible to extreme cold. According to Hasekura Reiri, although the use of multiple powers like a Dual Skill is handy, it only achieves that effectiveness through the use of rare materials and the control mechanism (the control core being machinery) is substandard at best.

The prototype weapons are capable of limited reproductions of multiple esper powers used by Tokiwadai students, not particularly strong but capable of switching between them. According to W. G. Waitley, each of the Attachment Dark Matter's reproduced powers are Level 3, with an estimation that they should approach Level 4 when combined. One reproduction was a calcium spear, intended to be identical to the ones used by Sukezawa Sena but revealed by electron scan to have a different osteoblast and osteocyte sequence. Other reproductions include a non-solid bullet, possibly based on Aero Shooter, ribbon control meant to resemble Enjou Kasumi's power, and a flame-type power.

Background
Attachment Dark Matter's development began after Antikythera acquired a biological specimen originating from Kakine. The specimen's quality was nowhere near the current Kakine and given capturing the real thing was not possible, Antikythera instead chose to analyze many different esper powers from multiple angles to try and overcome the fundamental roadblock in the development.

As part of this, Antikythera secretly acquired the services of Montgolfier, providing them with funding and downgraded data to them in exchange for test results from the manufactured prototypes, concealing their involvement.

First Year Arc
In the summer of a year before the main story, Montgolfier supposedly deployed operatives wielding Attachment Dark Matter prototypes in secret, attacking Tokiwadai Middle 's students using reproductions of other students' esper abilities in order to set off an inter-clique conflict and obtain observational data. However, an attack on Hasekura Reiri was actually the first direct movement against Tokiwadai, with the mastermind Sha Danshan's secret manipulation of W. G. Waitley through a reproduced Mental Out to act as her own scapegoat for the conflict, playing a key role in the decision.

After a thwarted ambush led to Montgolfier's involvement being detected, battles occurred between Tokiwadai students from the Hasekura, Mikagami and Sha cliques and Montgolfier operatives wielding the prototypes and reproduced powers, in addition to a separate battle between Antikythera guards using them and Hasekura Reiri after she traced their encrypted communications.

The majority of the operatives were completely defeated and captured at both Montgolfier and Antikythera headquarters, with the remaining wielders fleeing with Waitley being finished off by Sha Danshan as she came to dispose of her scapegoat now that it had served its purpose.

Trivia

 * Attachment Dark Matter bears some similarities with Equ.DarkMatter, manufactured from Kakine Teitoku and his Dark Matter after he was crippled by Accelerator and ready for deployment during World War III.   The two have a similar nature and naming scheme, but it is unknown if their developments are directly connected beyond the use of samples from Kakine and the intended goal of reproducing his ability.
 * Toaru Kagaku no Railgun editor Ogino Kentarou would subsequently mention during a Q&A session, with regards to the quickly-deteriorating biosamples from Kakine that Antikythera used in the development of the Attachment Dark Matter, that Antikythera's basic research formed the foundation and later bore fruit in Equ.DarkMatter.