Yuna Yoon

Yuna Yoon or Yoon Yun-Ha (Hangul: 

윤윤하) is a support character of Wind Breaker. she is a student at Sunny High and is s the headstrong twin sister of Minu Yoon .

Personality
Between the siblings, Yuna gets along more with their father and step-mother. An incident from the past has yet to be revealed has caused great strain on their family. Yuna cares a lot for her brother though she is clearly tired from the constant arguments. She continuously tries to talk Minu into coming home because she worries about him couch-hopping (from Jay to Vinny's house). Yuna is bored with her current life, having expected more romance and drama instead of the humdrum life of a high school student and she complains about it in the beginning. To her friends, she is a very dependable person. When she first met Dom, she got him interested in being a better person in school and had him think about what he wants to be outside of school. Her kind behavior causes him to fall for her, much to her consternation. When she finds about Mia's crush on Jay; she attempts to help her by setting up a student council meeting for them to make a true connection. She also visits Mia when she is going through a serious depression episode due to bullying.

Yuna doesn't take much crap from anyone if she does not know them or like them. She attacks Dom if he annoys her, and readily tells guys who flirt with her to screw off. This attitude of hers sometimes causes trouble and that is when her confidence flees. Yuna is more willing to pay people off than fight them if she is certain she cannot handle what is going on. She hates to see people fighting, especially Dom who she once made promise to never fight in front of her again.

Appearance
Yuna shares Minu's auburn hair, but she wears her in a pixie cut. She usually wears the Sunny High uniform without the red jacket, but a yellow sweater. When she's outside of school, her fashion style is close to Tomboy.

Minu Yoon
Minu is Yuna's twin brother. They argue and fight like regular siblings, but always take care of each other when the time calls for it. She tells Minu to back off when she notices he starts having feelings for Mia, but that's mostly because he started acting like Dom (who has a crush on her) in a similar fashion. Yuna, unlike her brother, is not bothered by how wealthy their family is. She worries about her brother a lot when he's kicked out of their home and goes out of her way to ask him repeatedly to come back. Resentment starts to build up as their mother's mental state deteriorates. At their mother's funeral (who died from a suicide), Minu is betrayed by Yuna's ability to get along with their father and stepmother like nothing happened. Yuna blames herself for their mother's death and shouts that to Minu.

After the funeral, they are no longer on speaking terms though she is sure they will again someday.

Mia
Mia is Yuna's best friend. She tries to help Mia build up her confidence with varying success. When she finds out about her crush on Jay, Yuna attempts to help get them together to be a good friend. They are regularly seen together and care for each other a great deal. When Mia is depressed due to bullying, she and Shelly give her advice on how to deal with what she's going through. They both go to the mountains with the Hummingbird Crew to cheer them on through their intense training, so much so that they come back to school color-less like the others. Mia is the only one who points out the possibility of her also having feelings for Dom, though she mostly rebukes the idea out loud. When she and Minu are no longer talking, Mia tells her that she's worried because she misses them always being there for each other.

Dom Kang
Yuna is mostly exasperated by Dom and his crush on her. When she first met him, he had been a delinquent, always getting into fights and not caring about his actions. She readily sought him out to demand he stops being such a troublemaker and to start caring about his life. She is the first person to make him consider his future, and that interest causes him to grow feelings for her. For the most part, outwardly she usually finds Dom to a complete weirdo and even goes as far to tell him to stop stalking her whenever he comes near. Whenever he swoons for her, it freaks her out. As the story progresses, it's shodwn that Yuna does actually care and worry about him. She does not like the fact that he gets into a lot of fights, and even goes out of her way to make him promise not to or she'll never talk to him again.

She is always the most worried for Dom whenever they watch the Hummingbird Crew racing on the television. When he is hurt or sick she usually helps patch him up or gives him medicine. When they are training o the mountain, she helps put band-aids on his back (but she hurts him a little when he swoons about it). The first show of physical attraction she has towards Dom is when he shaves his head, so much so that she even demands to touch it.