Orochimaru found her after her village was destroyed. He asked how she survived and she told him that she knew a large group of people were coming so she fled. Orochimaru then took her with him.

When Sasuke and Suigetsu came to recruit her, she was against leaving and said she had to keep the prisoners under control, at which Sasuke told Suigetsu to release them and, despite her protests, released them anyway. But when Suigetsu left, Karin locked the doors and started to get affectionate with Sasuke and tried to convince him that the two of them was all that was needed. Sasuke was slightly startled by her straightforward personality, but was "saved" by Suigetsu whom cut down the locked door. Suigetsu was tired of waiting and wanted to get going, saying that Karin obviously wasn't interested. Karin denied that and said that she's going that way anyway and will accompany them for a short time. She continues to try to find reasons to be alone with Sasuke, and even took his sweaty shirt.

Powers/Techniques

Karin has yet to show what she's capable of, but she possesses incredible chakra-detecting abilities. While it's common for ninjas to be able to sense people's chakra, she is incredibly accurate to great detail and can even track people solely on their chakra. Karin also has the ability to heal others just by letting them bite her arm, and suck in her chakra, when Sasuke bit her arm (after being injured by the Eight-Tailed Beast) his wounds healed. It should also be noted that she had other bite marks on her arms meaning probably this isn't the first time she used this ability.