The year is 20XX...
An archaelogist by the name of Dr. Cain has been digging at the same site for a few months, but hasn't been able to find anything. After moving his digging site, he soon struck metal in the earth. Upon closer examination and digging, the metal appears to be a metallic capsule of some sort, with a note attached;
WARNING:
"X" is the first of a new generation of robots which contains an innovative new feature - the ability to think, feel and make their own decisions. However this ability could be very dangerous. If "X" were to break the first rule of robotics, "A robot must never harm a human being", the results would be disastrous and I fear that no force on earth could stop him.
Approcimately 30 years will be required before we can safely confirm his reliability. Unfortunately I will notlive to see that day, nor do I have anyone to carry on my work. Therefore, I have decided to seal him in this capsule, which will test his internal systems until his reliability has been confirmed. Please do not disturb the capsule until that time.
"X" possesses great risks as well as great posibilities. I can only hope for the best.
September 18, 20XX
T. Light
Seeing as how it has been about 30 years since his incapsulation, Dr. Cain opens the capsule and releases "X" from his confinement. Cain marveled at the capabilities of this "X", he possessed the ability to think on it's own, make it's own decisions, it seemed almost human. After seeing how incredible X was, Cain set off to create even more robots like X, replicas of the original, called "Reploids".
It wasn't too long before Reploids began to exist in harmony with mankind. X helped Cain out in his lab, but his ability to think made him question his true existence. Why did the famous Dr. Light created me?
A few months later, a reploid turned berserk on some humans and had to be contained and treated. Not too long later more cases of these berserk, violent outbreaks began to surface. Cain began to fear that without testing the reploids' reliability like X was tested, they would turn on humans and begin to cause serious trouble.
Around this time, the newest reploid type was created, containing the latest circuitry and most advanced machinery, named Sigma. Sigma was assigned to contain these reploid berserkers, named "Mavericks" and to deal with them appropriately, forming a team of "Maverick Hunters". However, the same condition soon influenced Sigma himself and he turned against the Maverick Hunters and waged war. X decides to join the fight and bring peace, and along with the new head of Maverick Hunters "Zero" they set off to bring Sigma down.