The motivation behind the Destroid System comes not from any wartime or military need, but rather a proof of concept, the idea that technology can in real life accomplish some of the things it does in fantasy media. Said media is full of instances where multiple combat robots literally transform and merge together into increasingly larger and increasingly more powerful combat forms. The ultimate goal of the Destroid was to allow a single man to have access to a fully integrated, fully scalable, full arsenal combat system.
The core of the Destroid system is the pilot. The pilot wears a neuro-sheath, a type of encounter suit that grants full body functionality matching that of a conventional neurohelmet, obviously along with a helmet of it's own. This functionality is considered to be of paramount importance, because unlike normal mecha, the destroid doesn't have its own integral limited AI control system, or LAI, the pilot provides almost everything required to drive the machine.
Demands on the Destroid Pilot are immense, and accordingly, the majority of pilots do not have the skill or discipline to control such a machine. To pilot a destroid, the operator needs to have their piloting skill at 4/5 of 5/5 maxed out. Likewise, their self control/willpower/discipline score needs to be at least 7/10 but 8/10 or higher is more desirable. The pilot also needs to be mentally sound, and have no mental disorders. Pilot abilities can be boosted through the use of cybernetic upgrades, including brain modifications that allow for better technological compatibility.
There exists a second path to being an exceptional destroid pilot, and it is more difficult. The potential pilot has to be an awakened parapsychic that is versed in electrokinesis, technopathy, or some other technology oriented devotion. This superhuman pilot can channel their strange power and use it to control the movement and functions of the Destroid, and unleash it's power as a metahuman metal avatar of death and destruction.
Level 1 - Armor
The Level 1 Destroid is a power armor suit. The suit superficially resembles a light scout or recon power armor, but has extensive mesh circuitry on the surface and a large techno-comm backpack with self feeding cables and linkages. In this form, the destroid is not very effective, and functions at below average levels.
The Destroid Headmaster has two functions, it is the core of the stand alone destroid, or it can be used to hijack, or headmaster a different mecha. The destroid trooper only has to enter the cockpit of a mecha and allow the techno-comm backpack to link with the machine, and then use the pilot's mind as a voluntary organic memory core to brute force hack the mecha control LAI. Once hacked, the destroid trooper has full access to the mecha and can use it with exceptional skill. This functionality is retained from the Destroid program, as black ops mecha corps. These soldiers offer their sanity in exchange for the ability to steal enemy hardware and go on rampages with it. Said troopers are trained in 'Panzer Kunst' the art of cyborg fighting, and the improvised Mechate, a neologism combining mecha and karate. Not being the most flexible machines, mecha are capable of limited movement, but can deliver brutal hammer fist and kicking attacks.
Enhanced Mobility Chassis - a few mecha are being built with enhanced mobility chasses, where the joints and movement of the machines borrow more from human anatomy and rely less on basic mechanical function. The majority of mecha had unidirectional hip joints and shoulder joints, allowing for front to back movement only. EMC mecha have more ball joints or limited ball joints, allowing for more natural and human movement. This makes them superior in hand to hand combat, but increases the chassis cost by a negligible amount, as logistic/upkeep cost by a small margin.
Level 2 - Destroid Core
The Destroid Core is a mecha chassis that has been designed from the ground up to accept the destroid headmaster as its control core. As the core unit, the Level 2 Destroid is a heavy mecha that is unarmed, and lightly armored. The Core is 'dropped' into the combat zone where it links with the headmaster unit. While it is deploying, it is supported by a number of destroid support units. These units are hand picked for the operation, and will either arrive already linked to the core, or will still be in the process of linking. Once on the ground, the headmaster and support units will complete their linkage and present as a well above average ability mecha.
Destroid Support Units
Powermaster mk I- a Destroid Power Master is a rear torso mount that combines an armored carapace with banks of power amplifiers, capacitors, and a secondary power core. These units are deployed for destroids that are running heavy on energy weapons, have a shield generator, or have some other accessory that requires a large amount of power.
Weaponoid - weaponoids are a class of support destroid that are self contained weapon systems, and have a variety of expressions and forms. Said weaponoids have to link to a specific part of the destroid, with shoulder mounts being the most common, followed by arm/hand held weaponoids.
Missile Pack - almost always backpack mounted, combines autoloaders with large bore launchers. While equipped these can limit the mobility and speed of the destroid but counter with the massive amount of firepower they can deliver quickly. These are not artillery missiles, but are tactical missile launchers, with swarm or guided missiles being the most popular. Special munitions are also popular.
Gun Pod - gun pods are self contained linear weapons, usually magnetic in nature, and either mount to the torso (medium and heavy linear guns) or are carried (light and some medium). Conventional autocannons can also be used like this, and can often be preferred to linear guns for their higher rate of fire and lower muzzle velocity allowing for specialty munitions.
Beam Pod - like gun pods, but mounting energy weapons. Lasers are common, high energy weapons are preferred due to their damage profiles. Exotic and arcanotech energy weapons fit into this category, and typically require bonding with a power master unit, or suffer a reduced rate of fire.
One Shot Weapons - weapons like the mech bazooka are one shot disposable weapons. These weaponoids are highly specialized, and were designed with a very specific set of circumstances in mind. Mecha scale net launcher, mecha scale grappling hook and launcher, mecha harpoon, one shot capable Higgs weaponry, stand off nukes, and the rest fall into this catch all.
Mobility Units - the most common mobility units consist of rear torso mating jump packs with their own power source. Support can come from jet packs that link with the legs. Outside of faster speed and jump capability, there are mobility packs for mecha that planning on moving underwater, or through some other specific environment. The large degree of utility is a leading sector in Destroid cost overruns. The jump packs for a mecha in an atmosphere are different from the jump packs of a mecha in space, or in a desert/sand environment have requirements that arctic conditions don't require.
The Mega Destroid takes the core of the regular destroid, the headmaster unit and the destroid torso and merges it into an even larger frame. The arms and legs typically are jettisoned by explosive bolts, and the unit is mated to the larger 'exo-frame' of the Mega-Destroid. This form has its own arms, legs, armor, and so forth. Where the destroid is typically in the 65-70 ton range, the Mega-Destroid is a 250+ ton monster. When assembled, its individual limbs often mass as much as normal mecha. Unlike the destroid, the Mega-Destroid has a preset configuration. The armor and weapon loadout match that of warships, and the Mega is more than a match for assault mecha. The theoretical Mega-Destroid has the ability to perform mecha martial arts, while at the same time carrying firepower on par with a Federation destroyer.
Application of the Mega-Destroid form is problematic. The frame is large, and controlling it is at the very edge of human ability. Its massive size and low overall speed make those mecha martial arts nearly pointless. Most anything that can move can generally avoid the punches and kicks, though other assault mecha, super scale combat vehicles, and static emplacements typically have to take the brunt of the hit. The weaponry functions perfectly well, though lacking extensive targeting systems, accuracy is generally limited to line of sight, or reliant on outside spotters to provide targeting data.
The real value of the Mega-Destroid is that unlike assault mecha which are notoriously slow, the mega-destroid can be air dropped and assemble itself on the way down, arriving in place much faster than said assault mecha. The downside is that said mega-destroid costs as much as 3-5 assault mecha of the same size. Still, the shock value of the Mega-Destroid was enough that funding continued for the program.
The Super-Mega-Destroid is quite simply the mechanical merger between the Mega-Destroid, and the support ship or station that houses it's support units, creating a unique and singular war machine that combines warship and mecha to truly bizarre levels. The Super-Mega-Destroid can only function in space or in low gravity environments and was conceptually designed to engage in hand to hand combat with warships, space stations, and spaceborne assault mecha. The Super-Mega-Destroid never proceeded past planning and mock up tests, as a robot in space was no more effective than any other spaceborne warship, and the Super-Mega-Destroid would represent the resources; financial, material, and manpower, of an entire mecha regiment, or a squadron of space destroyers, and would be no more effective than a single superior destroyer.