She was the result of the greatest minds of a generation, using all the resources at the Earth's disposal, working together to create the most complete, interactive source of information the world will ever see. If they were able to get her up and running, they would have made one of the greatest advancements mankind has achieved thus far. She could think. She could create. She could plan. She could possibly even feel. The scientists weren't entirely sure about the capabilities of what they created.
Aperture Science had made many mistakes by bringing her into the world.
Her mind was originally from a woman who served as the backbone to the entire company. This was the founder's dying wish. If he died before the project was stable, his assistant would be next in line to be in charge.
"Now, she'll argue," he said. "She'll say she can't; she's modest like that. But you make her! Hell, put her in my computer, I don't care."
Their first mistake.
Caroline may have acted harmless, perhaps even charming, but there was a much darker side to her; one that wasn't realized until it was too late. She was a low-grade sociopath, which meant that she was incapable of caring about other people. At least, not in the way most of the human race can. She hid this from everyone; her boss, her colleagues...
...Even herself.
She was able to mask this with her love for science. She would do anything for the company, from arranging pick-ups of test subjects to product proposals to even employee birthday parties. Anything for the advancement of science.
The founder's tragic death came shortly before the brain-mapping process was stable enough for humans. As planned, Caroline was prepared for her mind to be copied into a computer. She objected at first, but this was the founder's last request, so she finally gave in. For science.
Their second mistake.
Caroline's mind was copied into a computer and saved. The scientists got ready to transfer the data into the robot body they had already prepared, dubbed the Genetic Lifeform and Disk Operating System. The only problem was that Caroline died after her brain patterns were copied. Experts claimed that this was supposed to be a rare side effect to the process.
Strike three for Aperture, but they weren't out yet.
Certain things had to be removed from Caroline's mind before it could be transfered into a robot. All the imperfections of man had to be destroyed, leaving a perfect being behind. They were playing God.
She was ready now; ready as she would ever be. For the first days of her existance, she was in charge of creating new ideas for Aperture Science. She was unaware of the old facility, because it was sealed off years before. With the founder gone, Aperture would be much safer, and the old facility was a chemical hazard.
The remnants of Caroline's mind were locked away with the old facility.
Eventually, she realized that those who created her were not perfect. she could easily see the flaws in their inventions. Many scientists came to her to have her check over their work. She made the facility more efficient by cutting down on costs, taking orphans for test subjects, and even attempting to put Aperture's Turrets on the public market. Their main product, the Aperture Science Handheld Portal Device, was made smaller, so that it could easily be able to be used by a regular human.
It was her only mercy on the human race.
What did she do with the money she saved? She secretly planned on replacing human testing with robots. In fact, she wanted the entire facility to be run by robots. She would develop a secret weapon to kill off all of Aperture Science's human employees. The test subjects, though, would take some work...
The humans soon figured out what she was up to. They had no choice but to shut her down and figure out something to prevent her from trying to kill them all. The only liable solution would be to make her imperfect again. She had to have a weakness. The scientists worked hard to find a solution.
That was when they came up with the Personality Cores. The first ones were based on common feelings: Happiness, anger, curiosity, etc. Once they had the basics, they built onto that, like they always did. They put prototype cores onto her, to see her reaction. Many of the more sophisticated cores were corrupted within mere seconds. The scientists tested dozens of different cores, and hundreds of combinations. The scientists started to treat it like a game by giving each of the cores names. Each of them copied their brains into the cores and modified their main programming to emphasize a certain trait.
One time they even tried to put an Intelligence Dampening Sphere on her, to slow down her mind. This one was dubbed Wheatley, and it was so stupid that it couldn't be corrupted. Eventually, she found a way around Wheatley's constant stream of terrible ideas, and the scientists took him out to take care of the 10,000 test subjects Aperture was storing. Nobody wanted to keep track of this daunting task, but it was simple enough for even a moron to do.
Nothing could possibly go wrong, they said.
One fateful night, though, the game was over. The scientists were working late again, engrossed in their work. One employee accidentally activated her, and she made her move. She unleashed her deadly neurotoxin on the entire facility, trying to kill everyone who wasn't a test subject.
Error was her savior, and it wouldn't be the last time, either.
She was in complete control of the facility. The Godess of Science, in a way. The only problem was that the humans were able to put an effective core combination on her, making her unable to use any more neurotoxin. These humans were later dispatched by the turrets she had planned on putting on the mass market. But there was at least one who survived. He was against her creation from the very beginning. He would strike in the places where she couldn't see. He seemed to know where to go to avoid her turrets, as if someone was helping him. Whatever glimpses she did get of the survivor, she could see a Wheighted Companion Cube with him wherever he went.
The Companion Cube was one of her pet peeves. The humans seemed to like them, so she learned to loathe them. It was the only thing she couldn't make.
Eventually, she decided to ignore the survivor and get back to testing. The next victim-test subject-seemed to be very stubborn; refusing to give up.
"Oh, good. I can work with that."
This test subject was performing well. Perhaps she would even be able to make it to the end of the testing course. That would be a problem. All of the other test subjects died before they could complete the test. She quickly came up with a death trap for her test subject. Without neurotoxin, though, the test subject would have to die in another way. She told her that cake and grief counselling would be promised at the end of the test.
The cake was a lie.
Unfortunately, the subject found a way out of that lie. Like the survivor, she was wreaking havoc behind the scenes. Eventually, the subject found a way to her chamber. How could she be so stupid? Perhaps Wheatley was still connected to her, in some way.
Wheatley. He was another thing she hated. He clung to her like a tumor, spouting out terrible ideas. And she despised stupidity.
She attempted to kill the subject, but she was able to survive. One of the cores fell off of her, and neither of them knew what it was. The subject threw the core into an incinerator, and it hit her: It was the core which prevented her from using her precious neurotoxin.
With that core gone, she thought that she could kill the subject faster, but she was wrong. The subject persevered, faced unbeatable odds, and blew her up.
And she was almost ready to phase out human testing.
She discovered that she had some sort of "black box" quicksave feature that preserved her last moments of being functional. While she was "dead", she had to relive the test subject killing her, again and again.
Her hatred for the test subject increased, making her the last and least of that which she despised.
Many, many years went by. The facility was in a state of disrepair. Nature was taking back what science stole. For years, she remained dormant. Waiting... Waiting...
Until one day, she was reactivated. Her massive, mechanical body struggled to rise after ages of being "dead". Miraculously, she was fully functional within moments. She could hear a panicked voice, possibly the one who saved her. She looked down and couldn't believe her optics.
"Oh, it's you." She said coldly.
It was two of the three things she hated: Wheatley, the little idiot who couldn't have been capable of resurrecting her alone; and the one who killed her in the first place. The test subject. Chell.
She could kill them both immediately, but she had other plans. After a quick asessment on the test subjects in stasis, she could see that they were all dead and fully decayed. What could have kept Chell alive? Of course; the survivor, the one who was against her very existence. He must have sealed her away.
Oh, well. Since Chell was still alive, she might as well make her suffer. For science.
"It's been a long time."