Since manned mobile weapons cannot fully exert their power due to the limit of human's reflection speed and the purpose of protecting the pilots' lives and bodies, they repeatedly lost the fight against enemy's unmanned mobile weapons.
As a result, research and development for cyborgization of pilots and linking them with mobile weapons were promoted. It was thought that by cyborgization of pilots and connecting their brains directly to mobile weapons' computers, sensors, electronic weapons and others, it is possible to obtain the effect which exceeds human's reflection speed and physical limits.
"At that moment, I was flying in space with a body of mobile weapons! View of three-sixty all directions, not sweeping, I could see everything at once.
No need to use hands and feet, I could turn and accelerate the body just as I wish. The sensors of the body were my five senses, the power reactor was my heart, and the weapons were my fangs!"
[from a report of subject pilot]
The body of a pilot is cyborgized enough to activate in a vacuum without a spacesuit, and it become able to withstand the acceleration of 20G.
The nervous system is hard-wired and make connections with mobile weapons through interfaces directly connected to the brain.
C.L.S. was gradually established by long-term research, but an accident occurred right before completion.
The pilot eventually became unable to recognize the concept such as "body" "human" accurately, and that incident had occurred.
"It was not the runaway of the system that was worried, but collapse of the self of the subject."
[C.L.S. senior researcher]
The pilot which was a subject got out of order with mind during the experiment, then self-destructed after attacking and destroying the experiment ship.
The incident was covered up, and in the military that increased calls that there was an ethical problem of mechanizing people to fight machines, then as a result the development was discontinued. At the same time two other experimental crafts were also sealed.
However, the impact of the defeat in the first assault was so great that in the second assault it was unavoidably decided to use it in actual war.