Karin Kurosaki

is the cynical and sarcastic daughter of Isshin Kurosaki, younger sister of Ichigo and fraternal twin sister of Yuzu.

Appearance
Karin is the dark-haired daughter of Isshin Kurosaki with her straight hair cropped to hang around her face, just above her shoulders. She is more often than not seen in sportswear, compared to her more femininely-dressed sister, with alternative shirts and trainers, giving her more of a tomboy appearance. Her eyes are large and dark and she sometimes wears a red cap upon her head and is seen with a soccer ball in many depictions.

Personality
Compared to her soft-spoken twin sister, Yuzu, Karin is the more authoritative of the two. Karin's tough exterior results from her mother's death; because she could not be useful around the house like Yuzu, she resolved never to cry so that she would not burden her family with her personal troubles. As a result, Karin appears to be the most harden an less emotional out of the two resulting in her not being affected by most events that would more or less bring tears to Yuzu's eyes. Despite these obvious differences, both girls remain close and share an equal concern for their older brother when Ichigo appears stressed or when he disappears for long periods of time. During these times, despite her own worries, Karin will reassure her sister, being there for her.

Karin is a sensible person and but is not above kicking her father in the head when she thinks he's acting unreasonable, which is generally a lot of the time. Despite this, she is still helpful around the clinic. Both she and Yuzu helping out their father as nurses when they can. She initially claims that she believes spirits do not exist; however, she can see them just as well as her brother Ichigo can. She can also sense them from great distances, which usually manifests as a headache. In spite of her attitude about spirits, Karin is willing to use her abilities to earn a little cash, such as her position as Karakura Red of Don Kanonji's Karakura Superheroes.

Karin actually knows that Ichigo is a Shinigami and, out of concern, wants to know why he's suffering.

History
Eleven years ago, along with her fraternal twin sister Yuzu, Karin was born to Isshin and Masaki Kurosaki. She was born with a four year old Ichigo Kurosaki as her only other sibling and shared with him the ability to see ghosts as clearly as he could. Little is known of her past other than the fact that she cried a lot in her younger days much like her sister.

Six years ago, one fateful night changed the lives of the Kurosaki family all together. While walking home from the dojo that Ichigo had been training at, he and his mother were attacked by the Hollow, Grand Fisher. Protecting her son, Masaki died as a result, leaving all three of her children motherless. Both of her daughters decided then that they had to mature much faster than usual, with Yuzu deciding to take over the housework and looking after the family. However, Karin felt useless compared to her sister and decided that her way of contributing would be to never cause her family to worry about her and so stopped crying all together even when she was injured or upset. By the current timeline, Ichigo admits that it's been years since he'd seen her cry.

Agent of the Shinigami arc
Karin first appears when Ichigo first arrives home, commenting to Yuzu that she should just leave their father and brother to their squabbling while requesting more food at the table and making fun of Ichigo's powers to see ghosts. She claims she does not care nor believe in ghosts despite being able to see them, much to the dismay of the Plus present in the room at that time. She derides her father for having a poster of their mother on the wall and talking to it constantly. She warns Ichigo to get away when Fishbone D attacks their family, injuring Isshin and capturing Yuzu. She, along with the rest of her family, except Ichigo, have their memories wiped of these events. Instead, they believe that a truck hit their house that night while they were all asleep.

Karin got sick when connecting with Yasutora Sado's parakeet, which had the soul of a young boy inside it. She was the first to realize that the bird was a boy who was dead and was being used by a Hollow to help it murder people. Ichigo says that it was the first time he had seen her cry since their mother had died. She is promptly put to bed in order to rest while Ichigo deals with the Hollow in question who is attacking Rukia. She seems to make a full recovery as soon as the boy's soul is sent to the Soul Society. She, Yuzu and their school friend witness Kon running across rooftops while in Ichigo's body, but when Yuzu and their friend say it is Ichigo, she dismisses the possibility and makes the others deny they saw what had happened.

Along with the rest of her family, Karin prepares to take the day off school in order to visit their mother's grave. On the way to the grave, she kicks her goofing father down to the bottom of the hill when he begins to really annoy her. When she sees Rukia Kuchiki waving at Ichigo and watching her brother get flustered by her sudden appearance, she assumes that there is something going on between them, saying that he's at that age. She talks with her mother in her mind, telling her that the whole family is doing alright. She is also seen comforting Yuzu while she'd crying by their mother's grave, trying to encourage her into not crying so much every year. She is then fooled by Grand Fisher in the same way that Ichigo had been as a child, with his bait standing over the cliff. She and Yuzu are then attacked and captured by Grand Fisher but are saved just in time by Ichigo just as Yuzu's about to be eaten.

Bount arc (anime only)
Note: Events occurring in this arc are only in the anime and do not constitute canon material.

When Ichigo and Isshin are fighting upstairs, Yuzu calls them down for breakfast and Karin wonders what their doing now. As their eating, Yuzu asks Isshin for an explanation as to what happened to his face and Isshin simply turns around saying nothing happened. Karin then asks Ichigo if he's been working out lately since he's gotten a few muscles lately. Ichigo changes the subject though and asks Yuzu and Karin if they've been doing their homework. Yuzu states that she got it done in hardly any time at all and then Karin states that Don Kanonji has been coming over a lot, saying that Ichigo is now his pupil. Ichigo begins to get worried and tells them that Kanonji doesn't know what he's talking about. All of a sudden Isshin gets up from his chair and kicks Ichigo in the face, sending him backwards. Isshin mocks Ichigo for not being able to react fast at all and the two of them begin fighting. Yuzu then tells them to stop fighting at the table. Later, after Ichigo returns home from school, Karin greets him and Yuzu tells him he's just in time for dinner. However, Isshin immediately begins fighting with Ichigo again, telling him he's late. Yuzu tries to stop this but Karin tells her to leave them alone and to think of it as a bonding experience for the two of them.

Arrancar arc
Karin later reveals during the Arrancar Arc, that she does, in fact, know that her brother is a Shinigami. She tries, unsuccessfully, to prevent Ichigo from confronting the Arrancar Ulquiorra Cifer and Yammy Riyalgo when they first arrive in the Human World. In the anime, she also has an encounter with Tōshirō Hitsugaya, realising that he is a Shinigami after she convinces him to help her win a Soccer match and when he saves her from a Hollow. She tries to find out where her brother is, but the Captain is also in the dark over Ichigo's Vizard training but he reassures Karin nonetheless.

Beast Swords arc
Note: Events occurring in this arc are only in the anime and do not constitute canon material.

While in a shop, Karin spots a strange humanoid spirit trying to eat onigiri without paying for them. After she stops the spirit, it disappears. Karin later finds it again in town and, seeing that the spirit is alone, she tries to befriend him. After learning that the spirit's name is Zabimaru, Yuzu (who cannot see the spirit) suggests Zabimaru comes back to their house for food since he is clearly hungry. There, Zabimaru continues to act bratty, saying he enjoys being by himself, to which Karin says he is being foolish to think it is better to be alone. While trying to entertain Zabimaru, the spirit starts to take a liking to them. After Karin and Yuzu fall asleep, Ichigo returns home and finds Zabimaru. When Karin awakes, she sees Zabimaru arguing with Ichigo. Zabimaru then turns his attention to Karin, saying he's angry Karin brought him to her house and runs away. Karin quickly runs after him. She finds him fighting a Tōjū. The Tōjū, realizing that he could not defeat Zabimaru directly, chooses to use Karin as a hostage. Renji arrives and Zabimaru defeat the Tōjū. Zabimaru then brings Karin back to Ichigo and asks him not to tell Karin about Zabimaru. Upon awakening at her home, Karin asks Ichigo where Zabimaru went. As Ichigo pretends not to know, Karin realizes that Zabimaru is fine.

Powers and abilities
Spiritual Power: Not much is known about Karin, but she is able to at least see spirits like her brother Ichigo can (prior to him obtaining Shinigami powers). Tōshirō Hitsugaya also mentions, in the anime, that Karin has high spiritual power for a Human, as she is able to see him.

Enhanced Strength: As demonstrated in the anime, her kicks were strong enough to hurt weak Hollows.

Keen Aim: Karin is also talented at soccer which would strengthen her physical power. She defeats weak Hollow's by kicking a soccer ball at them.

Quotes

 * (To Yuzu Kurosaki about ghosts) "Whether you can see them or not, as long as you don't believe, it's the same as them not existing."