Bio-Key is a technology unique to the Eternal Champions series. Developed by the Japanese government around 1994, the device would eventually develop into technology powerful enough to create The Overlord and forever enslave humanity to the computer world.
History
At some point prior to the Eternal Champions series, the Japanese government were developing a form of warfare that would blend technology and thought into a perfect human breed of warrior. Nakano Industries were interested in this technology and hired government insider Tashida to steal the plans without their knowledge. Tashida was successful and presented the plans to Nakano. After this, development of the software advanced quickly and Nakano was able to build a mecha loaded with missles and ray guns that could be activated with a single thought or glance. The nine Eternal Champions of the future attempted to stop Nakano from reaching his dream of becoming a timeless, global name in warfare and seemed to have succeeded. Unfortunately, Nakano survived the onslaught and also discovered a Bio-Keyed gun at the bottom of the ocean, renewing the research with increased vigour.
The next few centuries of the research weren't well chronicled, but it would appear that Nakano achived his goal of becoming infamous thanks to Bio-Key research. By 2345AD, Bio-Key weaponry was everywhere. The Cyberdome was a gladiator-style arena dedicated to the combat of super-soldiers grafted with Bio-Keyed weapons on their arms. As Nakano predicted, the guns could simply be fired with a simple thought, proving them to be highly effective warriors. It is unlikely that this technology stayed merely within sports and would have been used across the world in military conflicts. R.A.X. Coswell, one of the Champions, was one such cyber-fighter and returned here with five of his teammates to pick up some Bio-Key tools to fight Nakano with in the past. The heroes became embroiled in a tournament to the death, but escaped just in time to rip a Bio-Key weapon from somebody's body and returned to 1994.
By the time "the future" came around, Bio-key technology had completely taken over the world. Misuse of the technology had resulted in a sentient being known as The Overlord conquering humanity and replacing the thinking world with robots. The research had become so powerful that humans were no longer able to think for themselves, many of them forced to visit The Dream Bank and enter a permanent dream state. It was because of this that the nine Eternal Champions were formed and sent into the past to retrieve the plans, delete all knowledge of the Bio-Key from Nakano Industries computers and kill the one responsible for this mess in the first place. Since they were not succesful, it would seem that the Bio-Key still looms large over the world.