Karin (香燐) is a former subordinate of Orochimaru who assisted him in his experimentations and was left in charge of one of his bases while he was away. She has red eyes, matching hair color, and an unusual hairstyle: her hair is short and unkempt on one side and long and combed on the other.
Karin lived in a small village that was burned out during a war. She was the only survivor, completely unharmed. Orochimaru randomly found her after that and asked how she survived, and answered that she could tell huge groups of people were coming. Orochimaru then brought her to Otogakure, where she served as a jailer at one of his bases. Unlike the rest of the team, Karin was indeed loyal to Orochimaru, going as far as to refuse to release Orochimaru's prisoners even after his defeat.
Karin has a fluctuating personality; she will at times appear tough and in control, and at other times will appear annoying and highly flirtatious. This annoys both Suigetsu and Sasuke, but she attacks Suigetsu, whenever he voices his opinion. She, like many girls in Konoha before her, has a huge infatuation with Sasuke Uchiha. Her infatuation, however, is an obsession to the point of fanaticism. For example, when Team Snake was resting in a village to take care of the wounded Sasuke after his battle with Deidara, Karin planned to drug Suigetsu and Jugo to "ravage" Sasuke's unconscious body (although her plans were ruined upon sensing the Konoha shinobi trailing them). Later in the manga, she reveals that she has kept one of Sasuke's sweat-drenched shirts. Karin also implies that a team consisting of just her and Sasuke would be much better
Karin's special ability, the Mind's Eye of the Kagura, allows her to track specific individuals through chakra, seen when she is able to discern that Jugo is not among a crowd of prisoners through the standard concentration pose for molding chakra. It also allows her to pick up chakra from long distances and notice changes in an individual's chakra. Kakashi Hatake surmises that Karin is a particularly skilled chakra-sensing ninja, as she is not only able to tell that his group is approaching, but can also sense how many of them are present and that one is a dog. Karin also has the ability to heal others by letting them bite her, and suck in her chakra.[1] It should also be noted that she had other bite marks on her arms, chest and neck.