Vertical maneuvering equipment (Before the Fall Manga)

The vertical maneuvering equipment (立体機動装置) is a set of experimental equipment developed by inventors Angel Aaltonen and Xenophon Harkimo that allows for great mobility when facing Titans in combat. The equipment enables the user to fight in a 3D space as opposed to a 2D one. The equipment itself takes the form of a body harness that encompasses much of the body below the neck.

History
During the early days of the Survey Corps, a prodigal inventor named Angel Aaltonen expressed dismay that the soldiers were woefully under-powered when fighting against Titans outside the Walls. His assistant Corina theorized that the primary disadvantage is due to the size of the Titans and they could possibly try to build a device that would eliminate the height difference. Intrigued, Angel would immediately start brainstorming ideas and developed a prototype model. During a trip to the Industrial City, he presented his device to both his friend Sorum in the Survey Corps and fellow inventor Xenophon Harkimo; both were impressed by it and saw the possibilities. Xenophon agreed to work with Angel to improve and streamline the device.

The first improvements occurred after the Titan Mammon invaded Shiganshina District, killing numerous citizens including Corina. Learning later that the nape of the Titan's neck was the weak spot (after participating in two expeditions with the Survey Corps), Angel continued to work on the device and incorporated iron bamboo into the design of the device and as a stand-alone weapon to compliment it. However, Angel losing his sight and going into self exile stalled production of it for some time; Xenophon took it upon himself to carry on in his friend's absence and would work on the device for the next fifteen years.

However, Xenophon would figuratively hit a wall and cause production to stall once again. Eventually, two teens named Kuklo and Cardina would be sent under Xenophon's care; they were tasked with testing the device and took notes on their observations. While this would help work out some of the flaws in the design, Xenophon was not be able to progress as much as he initially hoped. Eventually, Angel returned out of his exile thanks to Xenophon's apprentice Sharle Inocencio and the two inventors renewed production once more. Stripping the design completely and working from the ground up, the device was finalized and christened as "vertical maneuvering equipment."

Versions
Known predominantly as "The Device," it was not until much later that the gear was officially called the vertical maneuvering equipment. As it went through production, there were several iterations made since its conception.

The first prototype of Angel's device was rather large and cumbersome, with the user wearing it much like a backpack. The control mechanism was initially along the lines of a grappling gun and designed in the shape of a pistol. It was also only able to move vertically in space, something that Angel inadvertently discovered as he tested it. A pull of the trigger on the grappling gun would fire the anchor and simply releasing it would pull the user towards it. Due to it being the first prototype, no weapons were initially designed to compliment it; as work continued on the device, Angel would later use a small dagger made from iron bamboo after seeing the material cause damage to a Titan during an attack in Shiganshina District. It would not be until much later when a proper weapon was designed by Angel to compliment the equipment.

In the second prototype, the most notable improvement over the first prototype is the size: While the first prototype was a cumbersome backpack, the second prototype is similar in size to the final model, reducing the size and weight considerably. Angel also managed to convert the gas canisters that power the device into rectangular boxes and aligned them along the sides of the user, as well as modifying the control mechanism to be more easily used one handed. The anchors are now also fired from the hips, rather than from a control mechanism like in the first prototype. It is this version of the device that was used by Angel to kill a Titan.

Angel began working on the third prototype of his device shortly before his exile, with Xenophon taking over in his place soon after. The device is now slightly larger than the previous iteration and allows for the user to move both vertically and horizontally. To facilitate this, the anchor launchers now had handles to allow the user to point them in different directions. However, this required four wires, which increased the weight considerably to approximately twice that of the second prototype. Also, this was the first iteration that had a means to protect the user in combat, as Xenophon would include a sword made of iron bamboo that was stored on the user's back.

The final version of the device that would later become the vertical maneuvering equipment was made through the combined efforts of Xenophon and Angel, along with Xenophon's apprentice Sharle Inocencio. The device was reworked from the ground up, with the primary housing gears and mechanisms moved to a small compact device worn along the back and the gas canisters that powered the device were attached to boxes worn along the sides. Three major flaws were discovered in the previous versions, which were fixed in the final version:


 * 1) It was initially believed that the device only allowing vertical movement was a flaw and the third prototype sought to fix this by allowing for horizontal movement as well, which however made the device quite heavy. It was ultimately found out that this was unnecessary and the most effective system would be a lightweight system with only two wires whose angles are freely controlled by the users body movements. Due to this, the handles on the anchors that allowed for horizontal aiming were removed and thus were also the wire-housings that allowed for horizontal movement, significantly reducing weight.
 * 2) In the prototype models, a major issue was the need to have the control handle in one hand and wearing the weapon in another hand, which made the system quite unwieldy. While Angel and Xenophon struggled to find an answer to this, Sharle recommended combining the weapon and the control handle into a single device. This feature was incorporated into the final model. The final model also incorporated snap blades stored inside the boxes at the side of the user that easily attach to the grips. The blades were also now made of ultrahard steel rather than iron bamboo, which is not quite as tough but is sharper yet still resilient while also being incredibly light, making it the most effective anti-titan weapon available. In addition, the boxes were modified to hold spare replacement blades in case the primary ones were ever broken or destroyed in combat.
 * 3) The final major flaw in the second and third prototypes was that it is highly difficult for the human mind to get used to firing anchors from one side of their body while the control handle is on the hand of the other side of the body. To solve this issue, control handles were now held in both hands, with the handle held in one hand solely used to fire the anchor from that side of the body. The controls also had considerably more functionality than before. The control mechanism now contained two triggers, with the upper trigger used to fire the anchors and the lower trigger used to retract it, with a lever in front of the trigger guard used to release gas. A switch close to the blade would release the blade while a small thumb-operated switch is used to aim the anchors on the vertical axis.

Training
Due to the unorthodox design and the fact only three people were ever seen using it, there was initially no training designed to show how to operate the vertical maneuvering equipment. Eventually, both Kuklo and Cardina would take down notes while the other ran tests and, with the help of Survey Corps captain Carlo Pikale, came up with a training regimen that would provide a start in training potential users. They included logistics tests focused on improving stamina and aptitude devices to work on the recruit's ability to stay balanced in mid-air while wearing the equipment.