Manga appearence: Chapter 348
Birthdate: June 20
Age: 16
Height: 162.6 cm
Weight: 45.8 kg
Gender: Female
Blood Type: AB

Previous Partner(s): Orochimaru
Affiliation: Akatsuki
Previous Affiliation(s): Otogakure, Land of Grass
Team: Hawk

Backround

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.
However, Sasuke had at some point noticed her at the time of his defection
and had decided to use her in Team Hawk long before he rebelled against
Orochimaru. 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.
Suigetsu has mentioned (perhaps as an empty threat) that Karin did something to
Sasuke in the past.

Part 2

Hunt for Uchiha

Sasuke Uchih recruits her as a member of Snake. While Sasuke admits she may be troublesome, he also notes that her special abilities make her useful. She also seems to have a liking for Sasuke, implying to Sasuke that a team consisting of the two of them would be much better than one with Suigatsu or Jugo. Once the team is completed, Sasuke sends "Snake" out in multiple directions to try and locate Itachi Uchiha. While on the search, Karin passes Sakura Haruno, though the two do not acknowledge each other. After Deidara's suicide explosion, the rest of the team regroups and takes Sasuke to an inn to recover. When Karin went out for supplies, including a drug that would allow her to "have her way" with Sasuke, she sensed the 8-man squad approaching, and warned the team. It was her plan to use Sasuke's old clothing as a means to distract the Squad from catching them. When they finally got back on Itachi's trail, Karin stayed behind with Suigetsu, Jugo, and Kisame as Sasuke went ahead to battle Itachi.
Karin, and the rest of "Snake" were present with Sasuke and Madara Uchiha when he renamed the team "Hawk" for their new goal; the utter destruction of Konoha.

Hunt for the Eight-Tails

Later, she and the rest of the team go to the Lightning Country to capture The Eight-Tailed Beast's When theyfoundhim, Karin sat on the side lines and watched the others fight Kirabi. Soon, after she started to mock Kirābī's rapping abilities as Sasuke began to fight him. Karin believed the fight was in the bag as Sasuke began the fight but she saw proven false as Kirābī easily mortally wounds Sasuke at the fight's beginning.
Karin immediately rushed to pull the dying Sasuke out of the fight as Suigetsu and Jugo kept Kirābī busy. As she pulled the swords out of Sasuke's body she exposed her right arm, riddled with numerous bite marks. She then pleaded for Sasuke to bite her arm and as he did her chakra healed his wounds. Sasuke acknowledged that Karin had saved him as she doubled over in pain.
As Kirābī got bored and attempted to leave, Karin used her chakra sensing powers to locate him. Kirābī then used his demonic chakra to charge at her, Jugo, and Suigetsu but Jugo rocketed them away to safety. After Sasuke was yet again critically wounded by Kirābī, Karin revealed that her chest was also covered with bite marks and she attempted to save Sasuke. She was then stopped by Jugo, claiming she didn't have enough chakra to save Sasuke from such a great wound; so he asked her to help him heal Sasuke. She then watched in horror as Kirābī transformed into the Eight-Tails. Karin then helped Jugo move Sasuke as Suigetsu held the Eight-Tails off, but as he was defeated even Karin, who despised Suigetsu, felt sorry for the pain he was in.
It seems that when Sasuke used Amaterasu on the Eight-Tails, Karin almost got hit with one of the tentacles, but Sasuke used some sort of Chidori variant to cut the tentacle off. While Karin was trying to recover, the Amaterasu spread and hit her. Sasuke put out the flames with his Mangekyo Sharingan and had Jugo use his Cursed Seal to elongate his arm to grab Karin out from the water.
With the mission over, she was carried away.

The Wait for Pain

As her team rest up, Karin is shown to have now changed her look by putting her hair in a ponytail. She scolds Suigetsu about his anger towards getting his sword left behind. She then claims that Suigetsu should be lucky that they saved him at all. She then notices that something is wrong with Sasuke but as he brushes it off she detects an enemy outside their base which Sasuke and Jugo go to investigate.

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 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. 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.