The Human Medium
The Synth is a humanoid surrogate funded by Candella Corp. With a life-like appearance, it's capable of doing anything humans can except defecation, making them an almost perfect puppet. The user can feel all the senses in the environment as if their spirit possesses into another, while the actual body still intact.
After a successful demonstration, it's been targeted for patients with any physical disorder in their hospital. Although it can be used in much more dangerous jobs like rescue missions or the military, that would be possible in future development. They only need a single question before marketing this to the public:
Where is it now?
According to scientific reports on paralyzed patients, although their body is unable to move, the brain is still healthy and functional. So, it would be good if they can find a way to use only brains to return to normal life.
The Synth solves this by connecting it via a neuron reader worn by a user. Before they can recognize the flicking of an electronic switch, their vision goes pitch back, and wake up with the synth's vision. It comes with the cost of the original body becoming unconscious. So it's highly recommended to find a proper place to keep the body safe.
It also requires high-speed internet to ensure its functionality due to transceiving complexity, making them available theoretically—only in the city.
The Synth is made of advanced circuitry and a titanium skeleton. Unlike any robot, it uses an artificial synthetic muscle with the combination of high-powered noiseless motors to provide strong, flexible but realistic body movement and appearance.
Synthesize skin covering the entire body provides it an ability to feel the surrounding. The sensory receptors are what make the creature feel real, and according to papers, the most difficult to replicate. Made of arrays of microelectronics weaving together, it uses special translucent materials to make skin lookalike.
The brain is what makes everything works. it's designed to look identical to the real one, and it's inside the skull. From central processor, transceiver, to primary memory, the brain has it all.
Last but not least, the energy. A biomass reactor generates power for the whole system. It can support life up to eternity, or a few weeks without eating thanks to reserved batteries. If all the battery died out the synth will disconnect itself and the user consciousness return.
The development team is led by a couple of robot engineers and neuroscientists, with funding from the Candella Corp. It's supposed to bring their fame and for the better world until one of them died in a tragic car-crash. The project was on hold and the remaining one take it back to their house as a way to recover. Nobody has ever seen them since.
The Man-made Soul
Artificial body need artificial intelligence. Candella Corp try developing the sentience for years but still can't figure out, until that guy come in with his homebrew one. They see an opportunity to aqquire them at all cost.