Cao Ling Shen, also called Rin Shen, is the younger maternal half-sister of Mao Lan. Her mother's subsequent marriage to Cao Da Hen made her his step-daughter and the half-sister of Cao Chun Yang. Ling Shen suffered severe abuse within the Cao family, primarily from Chun Yang who treated her as a live training dummy. This abuse escalated to nearly fatal levels multiple times due to Chun Yang's extreme brutality.

Fleeing the Cao family temple for refuge and a way to fight back, Ling Shen sought out Mao Lan to train in the Mao Family Juhe Fist style. Her core drive was mastering this art to one day defeat Chun Yang.

Ling Shen competed in the televised Prime Mat martial arts tournament. There, she showcased her growing skill in the Mao Family Juhe Fist, notably defeating the formidable Yagi Megumi, who utilized a blend of Judo and professional wrestling techniques.

Her bond with Mao Lan deepened beyond mentorship, anchored by their shared mother and mutual resistance against the Cao family's exploitation of martial arts. Ling Shen's journey focuses on overcoming the trauma inflicted by Chun Yang and securing independence through martial prowess.