Karin (香燐, Karin) 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 a sign of a fluctuating personality; Karin will at times appear tough and in control, and at other times will appear flirtatious. Karin's name means is made up for the kanji meaning "fragrance" or "perfume" and "sulfur". lt is also a homonym for the fruit "quince".
Background
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 Oto, where she served him as a jailer at one of Orochimaru's 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
Personality
Karin usually appears annoying, her usual victim being Suigetsu. However 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 keep one of his battered, sweat-drenched shirts for herself.
Abilities
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]. An example would be when Sasuke's wounds (after being injured to the brink of death by the Eight-Tails) healed after biting her arm. It should also be noted that she had other bite marks on her arms, chest and neck. So most likely, the marks of those bites are permanent.
Mind's Eye of Kagura
The Mind's Eye of the Kagura technique
Name: Mind's Eye of the Kagura (神楽心眼, Kagura Shingan; Literally meaning "Mind's Eye of the Divine Entertainment")
Type: Ninjutsu, Hiden Jutsu, No rank, Supplementary, All ranges
User: Karin
The Mind's Eye of the Kagura is a special ability only known to be used by Karin. This ability allows her to sense nearby chakra which is helpful when trying to track people.