Park Jung Hyun is the previous trainer of Moon Young Lee and participant in the Wild's League. She is in the same grade as Moon Young but only due to staying back a year due to family concerns. She made it into the finals in the previous year but was defeated by Queen within thirty seconds. She is defeated by Kim Ho Pae in a brutal manner, after she is tipped to be a favorite for the finals.
Jung Hyun is lean and of average height, being only a little shorter than Jae Gu in regards to height. She has green shoulder length hair that is layered, with short strands in the front that frame her face and a side fringe that is parted to the right. She has green eyes that match her hair color. In her first appearance she wears a sky blue sleeveless top and bold blue shorts with matching gloves. After her fight she is seen in the school uniform, and later seen wearing the tank top with a pair of blue and yellow sweatpants.
Jung Hyun is depicted as being easily embarrassed when being cheered on for by her school mates and fans alike. She is also helpful towards Jae Gu when he is trying to learn how to motivate Moon Young to train. She offers advice and often jokes about Jae Gu being in a heavily female populated school. She is confident in Moon Young's abilities to fight and shows her kindness and belief of Jae Gu's abilities to couch by showing him Moon Young's late night training regime.
Jung Hyun is first seen being cheered on by Moon Young who tells Jae Gu of her past achievements of being in the finals the last time she entered the Wild's League. She then is shown being unconscious after a fight with Kim Ho Pae who dislocates her shoulders and breaks her right arm. She is then visited by Jae Gu who asks for advice on how to couch Moon Young and Dal Dal. She offers advice on not allowing them to rush into a battle without having enough knowledge about their opponents; knowing very well that she failed to take her own advice on board in her last battle. When Jae Gu returns to ask how to get the two girls to train, she asks for his number which he gives before finding out the reason for her doing so is to have extra points towards her grades at the end of the year. Later on that night she calls Jae Gu and asks him to come with her as she shows him something important. It ends up she brings him to where Moon Young is training in an intense manner, she then states that Moon Young motivates herself to do better and that with natural talent fighters have an edge but are not always able to win without training. She then tells Jae Gu not to be too worried as it stresses them out and that the girls are able to motivate and train themselves.