The approximation of mobile media to physical human body started with portable then wearable terminals, and finally settled to implantable terminals which ushered civilization into a new era where man and machine were no longer separate. Such integration was realized by direct transplanting of communication terminals to the physical body, allowing the body and mind to interact immediately with standard computer and network technology. These implantables gradually took over the outdated portable/wearable technology, to be recognized as the prototype of "Cyberbrain."

After the ever-growing technology introduced the practical utility of micro-machines, cyberbrains became both safe and inexpensive. This caused rapid popularization of cyberbrains within countries that had little or no religion restrictions, such as Japan.

But the wide prevalence of cyberbrains caused social anxiety: people were exposed to risks of brain-hack because of their neural connection to the entire population using cyberbrains. The most serious brain-hacking crime was "Ghost Hack," a case where total individuality including past memories and body discretion of a certain person became the subject of the hacker. Various countermeasures were taken, such as the development of numerous protective walls and barriers along with reinforcement of regulations, not to mention security intensification within the neural network system.

But they failed to abolish cyber-crimes, thus resulting in a rat race: further development of protective walls and barriers, and the emergence of more intelligent and original hackers. (Yoshiki Sakurai)