Gaiaterra: Elysea's Conflict/Project NIKKE

After the war against the Collective, The Guardians had come to realize the power of superhuman psychics such as Yuri. And to prevent such a devastating war from happening again, they gathered forces, knowledge and resources to achieve one goal: create a task force made to counter these supervillains.

To do so, their military secret branch started working on creating a task force armed with the strongest equipment they made. One of these are special fighting androids, commonly called Nikkes.

Origin
Out of the four main combat divisions, the Nikke is the youngest. Their origins lie in the need for a combat-focus task force.

While easily capable of handling armies by themselves, the Rangers are also spread thin due to multiple roles and a decentralized command, such as Lightspeed Rescue focusing on disaster relief to the Lost Galaxy and Space Rangers tasked with protecting Gaiaterra's outer space and, in recent times, alien invasions.

International Rescue, while extremely fast due to the use of bleeding edge aeronautics technology, is still a rescue team first and for most, and often times the Tracy brothers are too busy protecting and evacuating civilians in warzones than fighting in combat. Not to mention the size of their aircraft also makes them impractical for some missions, mainly those requiring fighting underground.

The Investigation Team, while capable, is made for covert ops and investigation. And while their Personas are powerful they lack the equipment and skills to survive prolonged firefights.

Thus Project NIKKE was born. Using the Tacitus data to create the strongest droids ever built.

History
In the early days of its inception, the Nikkes were nothing more than large drones with above-average intelligence, often used to pilot vehicles that would become known as "Creeps", whose appearance was closer to a Scrin from reverse-engineered Tacitus data. With each successive iteration increasing its intelligence and shrinking the size of its motherboard, while also taking on a more conventional apperance. With the mark 4 Nikkes looking convincingly human compared to the large mark 1 to 3. But the latest mark 5 is better known.

Compared to the mark 1 to 4. The mark 5 Nikkes were either simply ordinary humans (compatible humans were referred to as "Suiters") with their brains transplanted into mechanical bodies, better known as 5B, or their AI was grown, better known as 5A. The latter of which is delicate work, especially since these Mark 5 AIs are designed to grow as they experience things. which especially has a high rate of failure if not monitored. One little mistake in the program code or core, or one little extra letter or space in the wrong place, and the whole thing could go haywire, with famous Mark 5A Nikkes being Alpha 5 (whose helmet is mistaken for being his actual head) and Mack Hartford, leader of the Overdrive Rangers. The early production mark 5s were more machine-like in appearance and outfitted with all sorts of technology like built-in missile launchers and leg-mounted rocket boosters, similar to the ark 4. Unfortunately, these augmentations caused cognitive dissonance between the human brain and the machine body, resulting in psychotic breaks and meltdowns, even the 5A units were affected due to having used the human body as a template. Additionally, the process of putting the brain in a cybernetic body would often have side effects, such as memory loss or personality alteration.

Later Nikke models were designed to more closely resemble humans, using handheld weapons and auxiliary gear worn on the body. While acquiring brains to transplant into Nikke bodies is largely still voluntary, sometimes a person critically injured or terminally ill will be made a Nikke to save their lives or, in a more cynical light, make use of someone who's bound to die anyway.

The Marks
The NIKKE Project can be easily categorized into five "Marks".

The Mark 1 Nikke is the second easiest to mass-produce and looks the closest to their root makers the Scrin. Compared to other AI it is smarter then most drones and automaton, which often needs to be remote controlled, but is dumber when compared to androids, and is overall larger. All Mark 1 Nikkes consisted of the vehicular Creeps.

The Mark 2 Nikke are slightly smarter, able to do multiple calculations quickly but struggle to respond to sudden changes. The Mark 2 are responsible for controlling the Naval Creeps.

The Mark 3 Nikke are closer to the intelligence of Androids, and is able to roughly adapt to sudden changes. The advance of the Mark 3 makes them reponsible for piloting the Flying Creeps.

The Mark 4 Nikke is the easiest to mass-produce and looks closer to humans due to the downsizing of its motherboard. Compared to their progenitors the Mark 4 are built as human, their metallic skeleton covered by artificial skin, and are able to think and plan. But they suffer from the inability to adapt or develop, often going in a loop when their communication to the commander is severed, making them efficient subordinates and soldiers, but poor warriors, as a normal person can learn, improve, realise where they made mistakes and take efforts to correct that. The Mark 4 can't. Thus the Mark 4 act as the soldier Creeps of the Rangers.

The Mark 5 is the most advanced Mark of the Nikke, and the smallest of the five. As unlike the previous Marks the AI of the Mark 5 are able to adapt, learn, and change when necessary, their intelligence being closer to a human, and the bodies being advanced enough that a human brain can be transplanted into a Mark 5 body.

Physiology
NOTE: This is only for the Mark 4 and 5 Nikkes due to their human-like design. The Mark 1 to 3 are closer to drones.

The interesting thing about the Mark 4 and 5 Nikke units are that they are built in layers, closer to a human body than a robot.

The first layer is a skeleton, made of a classified metal that rivals Talon Steel in toughness.

Next are the organs. From the brain, which is either a human or an AI chip, followed by an internal reactor powered by Morph X, the closest analog to a heart, that provides all their operational energy, removing the need to eat or sleep, though the former can be used for emergency refueling as their "stomach" breaks down the food to form Morph X energy. Doing so is purely psychosomatic to ensure mental stability. As Nikkes are not susceptible to the same diseases and conditions as humans, Nikkes can sustain themselves on contaminated food and drink, though they will find it an unpleasant experience.

The third layer is the muscles. The Mark 4s start off with significant lifting and gripping ability that never degenerates, but it cannot be increased unless the Nikke is physically remodeled or uses auxiliary equipment, the Mark 5 on the other hand uses actual muscles in their body and thus were able to strengthen them via training. This same strength factors into the weapons Nikkes use, which are much more powerful than standard human weaponry that humans risk taking a fall or even fracturing their bones from recoil should they try to fire them.

The fourth layer consists of padding. Which is a non-Newtonian gel serving as their soft sub-dermal armor to prevent shockwaves, from a bullet impact to explosions, from damaging their vitals. This had the side effect of giving the Nikke soft, jiggly skin and flesh, which helps lessen the cognitive dissonance, and made them rather attractive.

The final layer is the Nikke's skin which is composed of a material known as "Goddesium", which somehow replicates the feeling of human skin. Goddesium can also be used to manufacture top-of-the-line gear for Nikkes, though this is less prevalent as many would prefer to allocate the resources to actually making more Nikkes. Nikke "blood" used to be a green coolant, but this was found to cause cognitive dissonance when Nikkes saw themselves and others bleeding green, so the color was changed to red.

Due to the weight of their internals, Nikkes are incapable of even floating, much less swimming in water. This makes operations near large bodies of water or over frozen terrain filled with ice more complicated. Only a few Nikkes are adapted to deep water conditions (such as Helm and Aegis squad), who are tasked with naval patrol.

Nikkes are built with mental limiters that prohibit them from exerting lethal force against humans, at least when not in combat mode. The actual extent of this limit is somewhat murky, but at minimum, a Nikke cannot deliberately draw their firearm and fatally shoot a human unless they're designated as an enemy. This does not account for accidents such as in the heat of battle, the limiters can be circumvented by not taking immediate fatal shots.