Caroline Forbes is the best friend of Elena Gilbert and Bonnie Bennet. They use to share everything together. The trio also goes to the same high school and even in the same class in Mystic Falls. Caroline's mother is the sheriff of Mystic Falls and her father is outside town. Caroline seems to be a wonderful girl, that means she does not really care about others. She always wants to have the best looking girl and does everything to achieve it. This is how the people who do not know her well would describe her. But for her friends is Caroline a lovely person that in fact does care for her friends. Even Stefan realizes that after some time and does compare her to his best friend Lexi.
Caroline got converted to a vampire by Katherine Pierce. Caroline's mother, Elizabeth Forbes, could not handle this situation. As she has been hunting vampires her lifelong and now her daughter is a vampire too. After some time of not speaking together they finally met and talked. And now they are like a family again. Any as a new personality in the world of the vampires, Caroline remains loyal towards humans. Stefan teachers her how to control her new powers and with his help Caroline does not have to fear anymore that she could kill anyone by mistake.
Caroline & Damon:
Everything started when the Salvatore brothers came back to Mystic Falls. Damon already had an eye on Caroline since he saw her for the first time. They met the first time in a bar, where Caroline falls in love with him quickly. She invites Damon to go home with her and already in their first night of being together he shows her, his real face. He starts to compel Caroline and uses her as his private blood supply. Of course is Caroline scared and tries to fight him. Without having any chances to win that fight, she has to keep doing what Damon tells her. After a while of playing with her, Stefan talks to Damon and he can figure out a way to stop Damon using Caroline.
Caroline & Matt:
One day in the Episode "162 Candles" they feel something between each other and start a love story. In the beginning of the second season the things start to get weird between them as Matt is a human and Caroline is a vampire now. Caroline has to stop the relationship because she is scared of that she could hurt Matt. She does not have her powers under control yet. Matt can not life without her and tries to get her back. Caroline is still in love with him but in the end she tells him directly that they can not be together because she could kill him accidentally.
Caroline & Tyler:
Caroline never liked Tyler in the first place. But when Tyler became a werewolf they started to hang around a lot together. Caroline was helping him with his problem and was there for Tyler. As he did not know anything about vampires yet, Caroline told him she is the only vampire in town and because of that she could help and understand him with his transformation problem. Later on a few other werewolves came in the town and they took Caroline as a host and tortured her to threat Stefan and Damon. Tyler did not know any of that but still as soon as Caroline was free again, she quit the friendship with Tyler and he left Mystic Falls. Later on Caroline was together with Matt. The relationship did not hold that long and when they broke up Tyler was there to console Caroline. By that time they came together.