|Alias||Dr. Feng Jing|
|Eye Color||Light Green|
|Other Relations||Johannes Kleeman (Close Friend)|
|Manga Debut||Line 24; Don't Cry|
|Anime Debut||Episode 9; Command|
|Japanese VA||Sayaka Kitahara|
|English VA||Catherine Thomas|
Feng is a young woman of Chinese heritage with a slim, petite build and calm, light green eyes. During her debut, she had dyed light brown hair which was cut to a lower chin-length. Her fringe is middle parted and she has two strands of hair framing her face while the rest is tucked behind her ears. She originally had long, black hair which fell down past her shoulders. When asked by Lee regarding her sudden, drastic transformation, she claimed that she simply wanted a "change of pace".
After the six-month timeskip (in a total of nine months), Feng returned to her original hairstyle, albeit slightly shorter.
Feng is a caring woman who wears a good responsibility on her shoulders. She exudes a calm demeanor and can handle stressful situations level-headedly, especially in her job as a doctor. In casual interactions, she is straightforward and blunt, not afraid to freely speak her mind. She also has a habit of taking on more work than she can handle.
She is shown to be easy-going, carefree, and playful, especially with Lee. She tends to mess with him quite often. However, she cares deeply for him and embraces him as a true friend. Like Lee, she doesn't want to focus much on love or romance, simply wishing to enjoy life. However, she treasures and believes in familial and friendship bonds, and claims that people are not so simple-minded when it comes to abandoning those they feel are important to them.
Feng and Lee are very close. They have been friends for quite a while and Feng sells him blood. However, their relationship does not solely consist of selling and buying blood. They share a genuine friendship as two who are of the same heritage, while also finding common ground as foreigners (Lee being German and Feng, Chinese) living in Japan. They are very comfortable with each other and Feng cares deeply for Lee, as she was seen to be happy and very excited when Lee revealed that he had become "friends" with F Squad. She hopes that he'll become a member of that "family", too. She also doesn't care about the fact that he comes from an underground hospital, as she thinks of him as part of her own family.
Feng pushes Lee to go back to F Squad, his "home", but she has told him repeatedly that if he really doesn't have anywhere to go, she would happily let him live with her. Feng is determined to please Lee, having bought a toothbrush for him and prepared his favorite meals whenever he came to stay. Although Feng has stated that she does not like him romantically, she has mentioned several times that she would like to sleep with him. Likewise, Lee has also expressed a desire to try it. However, Feng is a bit fearful that their relationship will change if they cross that line. Still, Feng considers Lee a very important person in her life, and expresses to him that she will always be there to support and help him if ever he needs it.
After the six-month timeskip, it is seen that Feng and Lee are still great friends, as he had brought her over to the F Squad's former base, Bar Sakaki. Since Lee considers the F Squad as him home, it is implied that he wanted to share it with Feng since the dangers surrounding both of them had ceased.
- Feng is the one who made Lee's alias name, 'Hans Lee.'
- She is seen to smoke from time to time.
- Her nationality is Chinese.