Mechanized Infantry Units aka “Mechs”
Late in the 20th Century, as humanity withdrew from the coasts of Earth and began to build shelter for themselves in the form of massive Arcologies, new construction methods were required. To assist in these mega-scale construction efforts, robotics technology was scaled up and integrated with exoskeleton powered frames, creating the first Humanoid Construction Vehicles (HCVs).
The HCVs were extensions of the exo-frames that had already been used in the freight industry, and had been experimented with in the armed forces, but with limited success. Now they grew from frames about 9–11 feet tall, to 30 feet and more. The HCVs proved to be an enormous success and boon to the Arcology construction projects.
HCV technology followed humanity to the stars during the Diaspora, and were integral in the success of many colonies. Naturally, it was not long before someone had the bright idea to strap weapons to an HCV, and created the first MIU.
In the wars following the Diaspora, MIUs saw a great deal of combat, though nowhere near so much as their smaller ESPA cousins. MIUs were somewhat scaled down from the original HCVs, allowing for greater versatility while still allowing for the ability to carry weaponry that would normally be considered fighter-scale.
The appearance of the Hyperspace creatures made the real usefulness of Mechs readily apparent, as they were ideally suited to fight the incredibly varied and bizarre biology of these sometimes enormous creatures that humanity was suddenly confronted with.
Today, Mech technology (as MIUs and HCVs are known more commonly) has evolved, and with the severing of Hyperspace travel the designs for Mechs have incredibly wide ranges. Some, such as the MIUs like the Crusader or Ronin models, are far more common due to their mass-production during the last war, while others are practically unique in their designs, filling some specific role on some colony world.
To control a Mech of either variety, a pilot must be outfitted with a cybernetic implant that runs down the wearer’s back, along their spine. This device is called a Nerual Linkage, and connects the pilot to his Mech along a dozen different points in his spine, allowing for a neural interface with the machine’s software. Effectively, the Mech becomes an extension of the pilot, allowing for accurate use of extremities (such as fine motor skills) while still allowing the pilot to concentrate on more traditional cockpit controls.
The process of a pilot “docking” with their mech is uncomfortable to say the least, but far better than attempting to connect to a Mech without the NL. Technically, it is still possible to create a neural bridge without an NL, but this requires that the control taps pierce the spine (and everything in between) by force. As one might imagine, this is unbelievably painful.
Piloting a Mech without a neural bridge is next to impossible, conferring extreme limitations to movement or any motor skills, effectively limiting a pilot to using only the weapons.
For this reason, many Mech pilots “bond” with their Mechs over time, growing accustomed to how a certain model (or an individual Mech itself) fits him. In many ways, the feeling created by the Linkage is akin to that of wearing armor. The sensation is far from 1:1, but after piloting a certain Mech, one develops muscle memory for many specific functions. For this reason, if a pilot pilots a Mech for X amount of time, then switches to an entirely different model/configuration, the pilot must reset their NL bonus to base.