Name: Known as "Scaran"
Its/itself
Appearance:
Hunched over robot, entirely of some kind of strange shimmery material. If confronted, will stand upright to over 7 feet tall.
No appreciable face
Personality: Appears like a somewhat humanoid robot, but acts more animalistic. Prefers to slink around without being seen to scavenge for scrap metals and other materials.
Avoids detection wherever possible, but if it comes to a confrontation it'll be much like a bear- it will assess your threat level by body language, tone of voice, if you appear to have a tool or weapon drawn and how sharp or angular your overall shape is. Meanwhile it will stand up straight to its full height and become very still. It can also choose to freeze in place if it thinks it can avoid a confrontation this way.
Doesn't necessarily strike to kill, but if it has downed its opponent and can maintain stealth it really doesn't care what happens either way.
Apparently fully capable of speech but simply doesn't
Moves as minimally as possible to conserve energy, making it look very eerie in action, almost like witnessing CGI in the real world
The scavenging appears to entirely be a means to support itself, by finding scrap metal and other materials it can replace it's lost "cells" and spent lubrication
Backstory: Very much a mystery. Clearly some kind of wickedly sophisticated technology, but exact origins are hard to specify now. It's anyone's guess whether the tendency to be stealthy was by design, or something it learned.
Skills/powers: Its greatest strength comes from how it's body is built up of millions of nano-machines, held together with minute magnetic forces and an unusual lubrication substance inbetween the nano-machines that it can manipulate throughout it's system. This gives it a fully amorphous body that can be stretched, expanded, and reshaped at will, though at the cost of stored solar energy. (Doing common reshapes, such as changing the feet to be quieter based on terrain, would cost less because there's no more figuring out to be done)
Despite the mechanical appearance, the structure of the body makes it quieter to move than one might expect. Aside from footsteps, motions only make a soft noise akin to a falling pile of sand.
Also with regard to sound, it can recall voices and manipulate itself to mimic them. It's not perfect and likely wouldn't fool anyone since the replications sound somewhat metallic (think of a voice from a FAITH game), but if needing to cause confusion or psychological warfare it's a helpful trick.
Behaves animalistically, but has human capacity for intelligence- it can remember faces and places, use tools, learn languages, and problem solve. Worth noting is that it will pick up whatever tactics might be used against it, such as firearms, and figure out how to structure itself optimally to be a potent aimbot (which it would recognize is vastly optimal in terms of not having to move in a fight), but this can backfire too. If it doesn't witness someone reload for instance, it might not figure out how without witnessing it or finding instructions somewhere.
In a fight, it would prefer to use whatever weapons or tools are available to it to conserve resources, but if none are available it's own body will work just fine. It can increase the magnetic bonds to become incredibly strong, reform to have sharper edges, or even launch limbs as projectiles that will need to be reclaimed later. The finger turning into a spear trick from Terminator 2 is possible too, but the extra mass needed would have to draw from the forearm or something.
Defensively, it can reduce the density of it's form to soften blows, or even allow projectiles or knife strikes to phase through. If the body is separated, it can magnetically pull itself back together.
The nature of it's body means it would fully survive dismemberments and be able to fully walk off some if necessary. It's very likely to survive flattenings or explosions, but depending on the damage and cells lost, it would be at a great resource cost.
As a last resort or to fully intimidate, it can fully disperse to become a sort of angry dust cloud. Or, if dismembered, hold floating limbs in place instead of letting them fall to the ground. These tactics would require a lot of energy, ideal environmental conditions and would be especially susceptible to the elemental weaknesses below.
Weaknesses: The strange nature of the body also contains numerous caveats and weaknesses. First and foremost, fighting, reshaping and even regular movement costs energy and lubrication, so if these are to run out then the body would essentially die.
Being held together by magnetic forces, an EMP or strong magnet would cause tremendous stress on the cells, or even breakdown the body's function to keep itself together. Electricity would have a similar effect, but the lubrication acts as a insulator/ground so these are less dangerous.
Extreme heat from the sun can be shrugged off by the nature of the shiny material, as well as drawing solar energy. Extreme cold will not wreck the body, but it will cause the lubrication to stop working. Extreme heat from other sources will harm the body itself.
The body is mostly water proof, but full submersions could cause havoc on the lubrication.
In the instance the head is separated into pieces, they could continue to live similar to an earthworm. The "brain cells" work similar to a hard drive RAID array, where redundant material is stored in numerous locations to fill in gaps that might arise elsewhere. Assuming the rest of the body is also split into pieces, this would cause a great stress if the two halves reformed as two separate functional units. It's also possible they would no longer recognize each other and become completely separate (hostile) entities.
And ultimately, almost any confrontation, no matter how well it goes, will result in the loss of at least some nano-machines
Roles: Whatever works best, but the bestial nature probably makes it not well suited for any protagonist role
Notes: If you find the abilities OP I would have no problem if other characters discovered the weaknesses early on
I also don't really have any thoughts on what exactly happens with the collected scrap materials. If it can ingest it somehow or if it has to take it to some facility somewhere, it doesn't matter to me