Win Ling is Chun Ryeo's first apprentice as well as a martial artist and pill refiner that had much influence in the establishment of the Shen Mountain Fist.
She was originally the successor of a pill refining family that could make a special pill with the ability to raise one's level of martial arts. However, it was evident that her family would be targeted by both the Tiger Clan and the Viper Clan if its existence became known. So, her family kept their identity a secret and disclosed the existence of pill refinement to only a few of their most trusted family members.
After inheriting the pill, which was made throughout several generations, and the knowledge on how to make it, Win Ling also lived as an ordinary apothecary. At the age of 23 though, she gets caught up in a big feud after someone seeking the martial arts treasure reveals her identity to the Viper Clan. However, in meeting someone in the midst of it, Win Ling not only escapes from danger but also begins a new life as a martial artist.
Like how she studied various medical texts and pill refinement methods, Win Ling also collected, compared, and studied various methods when it came to learning martial arts, and her excellence in learning martial arts allowed her to reach a high level of mastery. As time passed, the number of martial arts skills she mastered increased. She organized what she had learned and alongside Chun Ryeo, refined them into a single martial art, the 'Shen Mountain Fist'.
Once Shen Mountain Fist was somewhat completed, Win Ling became concerned that its power may fall into the hands of someone unworthy. Thus, she wanted to make an empty scroll that would serve as a warning to miscreants who were only after the power of Shen Mountain Fist while teaching its true ways directly in person. This has much to do with the fact that she witnessed firsthand how if an 'unworthy person' obtains great power, they can destroy everything including themselves.
Even after achieving great accomplishments, she, accompanied by her fluffy white rabbit, continues to devote all her efforts into studying martial arts while traveling with Chun Ryeo as they continue to train and help others.