Caroline is a character that goes unseen in Portal 2, with the only traces of her being pre-recorded messages of her voice. She worked as an assistant to Aperture Science Corporation's CEO, Cave Johnson, which began in the 1950s and lasted until the 1980s. She had a lot of respect for Johnson and always stuck close by, even through properous times and the more troubling times.
In the 1980s, Johnson became poisoned after ingesting moon rock dust. This began his work on trying to find a way to store human consciousness in computers, so after his physical form was gone, his mind would still continue to live. As his time got closer to an end, the project wasn't complete yet. This prompted him to force Caroline to be inserted against her will, which was the creation of GlaDOS.
