The virus has swept the world. Although most people have become immune to the virus through serum injections, some people will mutate into "Yin Demons" under the influence of the virus. In order to fight against the Yin Demon, some humans transformed their virus-infected parts into prosthetic bodies made of black metal. In order to become "Purgers", they entered corresponding academies and began to learn combat skills.
Of course, there are also "(MP) maintenance personnel" who do not have combat capabilities, but have corresponding knowledge and provide services such as steel armor maintenance and upgrades to the "Purgers".
"Su Xingyu, what are you doing with my leg?"
"Well... You're awake. I suddenly had a new idea, so I wanted to upgrade your steel armor."
"Then don't secretly take off my legs while I'm sleeping! Pervert!"
Purpose: If a worker wants to do his job well, he must first sharpen his tools